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THE malposition, head-under-left-wing, affects from one to about 20 percent of the chick embryos which live through the first eighteen days of the incubation period. The incidence of the malposition has been described by Hutt (1929), Smith (1930), Hale (1930), Byerly (1930), Byerly and Olsen (1931), Hutt and Cavers (1931), and Taylor, Gunns, and Moses (1933). Byerly (1930), stated that the malposition was of doubtful importance as a bar to hatching. Data collected since that time have removed all doubt that it is usually lethal. Several factors which contribute to this lethal effect have been found. First, the malposition is often accompanied by obvious malformation and smallness of the affected embryos. Second, Hutt (1929) pointed out that the beaks of affected embryos are usually turned away from the air cell and that this may reduce the likelihood of pipping. Third, the direction of rotation of the body of the embryos . . .

IT IS common practice among hatchery-men to wait until eggs have been incubated 14 to 18 days before removing the infertiles. Although infertile eggs are easily detected at this age, by simply passing the tray over a group of lights, nevertheless much incubator space is occupied by them which could be profitably used if the infertile eggs were removed earlier. Still other benefits would be obtained if the two classes of eggs could be distinguished at an early hour of incubation. For example, a poultryman could quickly check the fertility of the eggs from his flock and a scientist could conduct certain experiments using only fertile eggs if he so desired. With this in mind, a series of experiments was conducted to determine the earliest and most practical time when infertile white and brown shelled eggs could be removed from the incubator. Preliminary investigations on this project were begun the . . .

Parthenogenetic tests, involving 345 young, virgin Beltsville Small White (B.S.W.) turkey hens and 15,131 unfertilized eggs, were conducted during 1970 and 1971. The hens involved were daughters of inbred and outbred sires and dams and represented progeny from various types of matings. Average levels of total parthenogenesis and embryos in eggs of daughters appeared to be inversely correlated with degree of inbreeding. The lowest percentage of total parthenogenesis (42.8% in 1970 and 44.4% in 1971) and embryos (9.8% in 1970 and 6.6% in 1971) were encountered in eggs laid by daughters of inbred sires and inbred dams. The highest percentages of total parthenogenesis and recognizable embryos (47.7% and 19.1% in 1970 and 49.3% and 27.2% in 1971, respectively) were found in eggs laid by daughters of inbred sires and outbred dams. Gradual reduction in numbers of embryonic lethal genes through inbreeding is suggested as one possible explanation for the marked increases encountered in relative numbers of embryos in 1970 and 1971 as compared to levels found in prior years.

SINCE it has become an established fact that egg production is to a considerable extent inherited, it is necessary, if one is to carry out a progressive breeding program, to know something of the inherent production qualities of each bird. In order to secure this information, some poultrymen have resorted to the use of the trap-nest. However, other poultrymen have found that daily trap-nesting is not practical on their farms, due to the time and expense involved. The author is of the opinion that if some short-cut yet reliable method of trap-nesting were to be adopted more generally, a systematic constructive breeding program would be considerably advanced. In the present paper one more method is suggested in the light of an analysis of records obtained at the National Agricultural Research Center. Many scientific investigators have realized the need of such a simplified method of trap-nesting. One group of investigators have . . .

THIS paper presents the results of one phase of a group of experiments and observations to determine the causes of malposition in chick embryos at hatching time. Malposition is one of the chief immediate causes of embryo mortality in the domestic fowl and is therefore a matter of very considerable economic importance as well as scientific interest. Hutt (1929) suggested that early orientation might affect hatching position and Taylor (1932) found such a relation for the malposition head in small end of egg. LITERATURE For more than a century investigators in biology have known that when the blunt end of the fertile egg of a bird, incubated for a few days, is held to the left of the observer and the upper portion of the shell removed, the embryo usually will be found lying on its left side with the head turned to the right and pointing away from the . . .

CONSIDERABLE losses occur every season as a result of low fertility and hatchability of eggs among the strains of Broad Breasted Bronze turkeys that now constitute the majority of the turkeys raised in the United States. It is estimated that of each 100 eggs incubated only about 55 poults hatch. If fertility and/or hatchability is inherited, then more poults can be hatched per 100 eggs set from flocks in which proper selection and breeding are practiced than from those in which little attention is given to those factors. Thus, considerable economic gain would result. The purpose of the present study was to compare crossbred matings with purebreds to determine whether or not efficiency in reproduction might be increased by crossing. A number of investigators have reported on the fertility and hatchability of various strains and varieties of turkeys and on the results of crossing different strains and varieties. Whitson, Marsden, . . .

A NUMBER of studies have been made of the effect of low holding temperatures on the hatchability of hens’ eggs. In general, these studies have shown that embryonic mortality is high after eggs have been subjected to storage temperatures of 40 degrees F. or lower for prolonged periods. Mauro (1923) stored two lots of eggs for 10 days; one lot was held at an average temperature of 32.9 degrees F. and the other at 57.2 degrees F. He found that the embryos in the eggs stored at 32.9 degrees F. did not develop when placed in the incubator. In contrast to this, he obtained a 60 percent hatch of fertile eggs from those which had been stored at 57.2 degrees F. for 10 days. Scott (1933) also found that low temperatures were harmful to hatchability. He stored two groups of White Leghorn eggs at average temperatures of 36.3 degrees F. . . .

THE data presented by Byerly and Olsen (1931) indicated that from 2 to 3.5 percent of all fertile eggs incubated contain at hatching time dead chicks with their heads in the small instead of the large end of the shell. In order to save the poultry industry the very large sums lost through this means, it is necessary to know the causes for this malposition and the portion of the incubation period during which those causes act. Byerly and Olsen (loc cit.) demonstrated that gravity is a very important factor in determining the hatching position of the chick embryo. The present experiments were designed to give information about the time of determination of the malposition head-in-small-end-of-egg and the mechanism of its determination. Data have been gathered coincidentally on the lethality of this malposition. MATERIAL AND METHOD Several lots of eggs were incubated for various periods in some one of the . . .

Sanctuary, (1925), Hutt (1929), Smith (1930), Hale (1930), and Byerly (1930), have reported and discussed data on malposition in the chick embryo, but no experimental work on the cause of malposition has come to the author’s attention. The present paper is presented as a contribution to the solution of the causes of malposition and to our knowledge of its importance as a factor in hatchability. During the earlier portion of the incubation period the embryo floats freely on the upper surface of the yolk. As incubation proceeds, the embryo turns to a new position relative to the overlying shell whenever the egg is turned. If the egg stands on end, this statement must be somewhat qualified because the ehalazae prevent the embryo from reaching the middle of the upper yolksurface. Since the position of the embryo in the egg is at first determined by gravity, it is reasonable to suppose . . .

EXPERIMENTS at the Agricultural Research Center, Beltsville, Maryland, over the past four years have repeatedly demonstrated that parthenogenesis occurs in infertile turkey eggs. The original observations made in 1952 revealed that 156 or 16.7 percent of 934 infertile turkey eggs laid 57 to 215 days following removal of the males showed an abortive development upon being incubated. In over 95 percent of the instances encountered, the development consisted solely of an unorganized growth of embryonic cells with no evidence of either blood or embryo formation. Since these initial observations, further tests have been conducted which substantiate the earlier findings. In these subsequent tests only virgin turkey females were used, and with few exceptions were separated from their immature male pen mates before 6 weeks of age. The tests conducted in 1953 as well as results to be reported in this study showed that more than 22.2 percent of all infertile …

A MAJOR factor in the cost of production of chicks is the excessive loss of eggs which fail to hatch. It has been estimated that approximately 30 eggs of every hundred placed in commercial incubators fail to hatch. Approximately one half of the eggs which have to be discarded are infertile while the remainder represents eggs in which the embryos for various reasons have died during incubation. It is with this group of eggs, the ones that fail to hatch, that this study is concerned. This investigation was undertaken to determine to what extent, undesirable characteristics found in certain eggs affect hatchability and to obtain information as to the numbers and distribution of such eggs. REVIEW OF LITERATURE Knox and Olsen (1936) studied the effect of tremulous air cells on the hatchability of eggs. They found that eggs 1–7 days old with tremulous air cells gave a hatchability of 56.7 . . .

TURNING eggs has long been known to be necessary in artificial incubation to secure satisfactory hatches. Until the development of Mammoth incubators, however, little attention was given to the manner of turnings eggs or to the number of times they were turned a day. Eycleshymer (1907) appears to be one of the first to report the effect of not turning eggs. He found that he obtained only a 15 percent hatch when the eggs were not turned as compared to 45 and 58 percent hatches when the eggs were turned two and five times per day, respectively. He further states “that position of egg is a factor of little importance.” Jackson (1912) found that eggs turned twice daily hatched slightly better than those moved only once a day and also that “eggs laid flat and turned twice daily gave better results than those kept in any other position.” Comparisons between . . .

THE immediate objective of the exploratory tests described here was to determine the effects of sustained low barometric pressures and of rapid changes in barometric pressures on the survival of day-old chicks. Some tests were also made at different temperature ranges, but due to time and other limitations under which the work was carried out, no proper analysis of the role of this factor could be attempted. There is little in the literature on the type of test described here. The papers by Rostorfer and Rigdon (1947), Britton and Kline (1945), and Stullken and Hiestand (1943) should, however, be mentioned as well as unpublished observations on birds made available to us by Dr. Paul D. Altland. SOURCE OF CHICKS Day-old, non-sexed Rhode Island Red chicks hatched at Beltsville were used in all runs except test 9 (Table 1); the exceptional chicks were 2 days of age at the beginning of . . .

IN THE fields of plant and animal genetics, there has been a considerable amount of experimental work crossing different inbred lines, distantly related individuals, and, in some cases, crossing individuals of different genera, species, or subspecies. Hybridization has been and may be accomplished in three ways: 1. Crossing individuals of different genera, species, or subspecies. 2. Crossing inbred individuals of different inbred lines. 3. Crossing individuals of different breeds and varieties. The progeny of genera, species, and subspecies crosses in the plant kingdom have been used with some degree of success in the formation of new types of plants. However, in the animal kingdom, progeny from wide crosses in large animals, whenever they are obtained, usually prove to be without economic value although the mule is an outstanding exception. Many crosses have been made between birds of different species and subspecies and in a few between individuals from different genera. . . .

PROBABLY most investigators in the field of nutrition have felt concern at some time over the variability among the individuals of any population with respect to their response to dietary influences. It is surprising, therefore, that so little effort has been directed toward the study of such variability. Bird et al. (1947) described a study of the variation in reproductive response of hens fed a diet now known to be deficient in vitamin B12. There was wide variation among the hens with respect to the hatchability of their eggs and the viability and growth rate of their progeny. These authors briefly reviewed the literature on the inheritance of resistance and susceptibility to dietary deficiency. Lamoreux and Hutt (1948) were able to select two strains of White Leghorns relatively resistant or susceptible to a riboflavin deficiency during the growing period. The authors believed that genetic differences between the two strains in . . .

IT IS well known that a marked variability exists in the rate of development of embryos of both chickens and turkeys. This is particularly evident when fertile eggs of either species are examined before a candling device during the first week of incubation. Hutt and Pilkey (1930) and Bernier, Taylor and Gunns (1951) found that these differences, in part at least, were associated with the length of time that an egg remains in the oviduct and the position of the egg in the clutch. These variations are apparent, not only after the egg has been incubated but are evident in the blastodiscs of broken out, newly-laid eggs. Hays and Nicolaides (1934) in discussing this problem suggested a genetic basis to account for some of the variability. Scott and Warren (1936) and McNally and Byerly (1936) found considerable variation among chicken embryos after the eggs had been incubated 39 and 48 …

NUMEROUS investigations using the domestic fowl have been conducted in recent years to determine the mode of inheritance of egg weight and relationship of this character with other factors such as body weight and sexual maturity. Many studies have shown that egg weight is inherited and furthermore that there is a relationship between egg weight and the factors mentioned. Hadley and Coldwell (1920), for example, observed that the largest birds in their flock of White Plymouth Rocks tended to lay the heaviest eggs. The results obtained later by Asmundson (1921), Atwood (1923), Jull (1924), Parkhurst (1926), Upp and Thompson (1927), Rhynehart (1929), Hauschildt (1929), Hays (1930), Atwood and Clark (1930), and Hall and Marble (1930) supported this finding. Marble (1930) observed a significant positive correlation between egg weight and body weight and he pointed out that the mean egg weight increased as the average body weight increased. In general then, . . .

ORIENTATION of the egg in the oviduct and during the act of laying may have a bearing on the production of the “egg bound” condition which is a major factor in the death of laying hens. Benesch (1922), Pittler (1924), and Fleischhauer (1926) have studied egg orientation from this standpoint. It has been suggested that when eggs are laid large end first or when they are turned during passage through the oviduct they are more apt to cause the eggbound condition. Before it is possible to evaluate this hypothesis, it is essential to know the relative frequency with which eggs are laid large end first and of the turning of eggs during the act of laying. The authors’ particular reason for conducting this study is the possible bearing uterine orientation and laying position have on hatching position of chicks. It will be shown in a subsequent paper that eggs found . . .

PHILLIPS and Warren (1937), in studying ovulation in the hen, described ovulation of 6 excised ovarian follicles clamped at the stalk to maintain turgidity. Four of these were returned to the body cavity where they ovulated, and 2, kept moist with Ringer’s solution, ovulated outside the body. Phillips and Warren also observed the ovulation of 40 unsevered follicles in celiotomized hens. All ovulations recorded by these authors occurred in follicles expected to rupture within about an hour following initial observations. Follicles removed from the ovary about an hour before the time of expected rupture, and maintained thereafter in saturated atmospheres or in approximately isotonic solutions at 100°F., have been found capable of ovulation independently of any means of increasing turgidity (unpublished results from this laboratory). These exploratory tests yielded, however, only 14 completed ovulations from 47 follicles. The present study describes a simple and dependable technic by which ovulation of . . .

INTRODUCTION FEVERS induced by artificial methods have been employed successfully during the past 15 years in the treatment of certain human diseases, particularly paresis, a form of paralysis caused by syphilis. Previously it was the consensus of opinion among most physicians, as Carpenter and Page pointed out in 1930, that a rise in body temperature was a sign of disease, as is pain, and that to establish the comfort of a patient the excess heat must be dissipated. The evidence, however, which has accumulated during recent years indicates that fever, as it naturally occurs, may be a valuable weapon of the body against an infection. In the case of humans, various methods have been used to induce artificial fevers. The two most common methods employed today are the short radio waves and the air-conditioned cabinet. In the use of short radio waves, the patient rests upon some insulating material and . . .

IN AN experiment conducted at the Bureau’s poultry laboratory of the Beltsville Research Center, Beltsville, Maryland, hatching eggs were purchased from a number of different breeders in different sections of the United States. These hatching eggs were packed in various ways before being shipped to Beltsville. Before the eggs were placed in the incubator they were candled and the data were compiled in respect to the condition of the air cell of the egg. It was found that many of these eggs contained air cells that were classified as tremulous. During this experiment it seemed quite evident that there was some effect upon hatchability as it was noted that the eggs with tremulous air cells did not hatch so well as those with normal air cells. Because of this evidence and its importance to the hatching industry it was decided to investigate this problem more fully in order to arrive . . .

INTRODUCTION IT HAS been estimated that more than a billion eggs are used for hatching purposes each year and of this number 12 million dozen, or 15 percent, are infertile. This means much needless expense in the handling and shipping of eggs which are worthless for hatching purposes. Discarding of infertile eggs at the source of supply and shipping only fertile eggs would result in a distinct advantage to both the shipper and hatcheryman. The shipper, on the one hand, could guarantee almost 100 per cent fertility and his transportation costs per fertile egg would be reduced. The hatcheryman would likewise benefit in that he could be assured of a greater number of chicks per hundred eggs set and make more efficient use of his incubator space. In view of these potential economic advantages, an experiment was undertaken to determine the feasibility of shipping pre-incubated hatching eggs and to determine . . .

INTRODUCTION SINCE 1956, parthenogenetic turkey embryos in considerable numbers have been encountered each season at Beltsville in unfertilized eggs of virgin Beltsville Small White (BSW) and heterozygous Bronze turkey eggs. Approximately 25% of all the parthenogenetic embryos encountered each year survive until the last week of incubation. Of these, only 3 to 8% of total embryos emerge unaided or are helped from the shell. Waters (1935) has shown that full-term chicken embryos (and presumably turkey embryos) from fertilized eggs get into abnormal positions and yet hatch. In spite of this finding, it was nevertheless of interest to examine some full-term parthenogentic embryos that failed to hatch and record the numbers found in three malpositions, each of which could be a barrier to hatching. Furthermore, the respective frequencies of these positions might furnish additional data on the original orientation of the embryos. MATERIAL AND METHODS Daily settings of unfertilized eggs from . . .

THE ability of the chick embryo to orient itself within the shell prior to hatching time is a subject of dispute. Hutt and Pilkey (1934) stated that if eggs are placed horizontally on a tray on the eighteenth day, and not turned subsequently, all eggs which hatch are pipped on the upper surface. They stated further that eggs turned on the nineteenth and twentieth days are pipped about equally on upper, lower, and intermediate surfaces. They presented no data to support their statements. Waters (1935a) presented data for 225 eggs turned four times daily after the seventeenth day and for 225 controls not turned after the seventeenth day. The turned eggs were pipped about equally on all surfaces, as Hutt and Pilkey stated, but the unturned eggs were also pipped about equally on all surfaces. Byerly and Olsen (1936) reported that about 5 percent of eggs not turned after the . . .

Since 1953 considerable work at this Station has been devoted to the study of parthenogenetic development in Beltsville Small White (BSW) turkey eggs. Most of the work dealt with the incidence of parthenogenesis as influenced by selection and by environmental factors. It also was of interest to determine how widespread this form of development was, and to what extent it occurred, in eggs of other varieties and strains of domestic turkeys. These tests involved a total of 3,048 unfertilized eggs from 116 young turkeys representing 9 different varieties, strains, and variety crosses. Three of the groups were secured from commercial sources, the remainder were from State experiment stations. None of the hens involved had been selected for a high incidence of parthenogenetic development. In conducting the parthenogenetic tests, the same general procedures were followed as those outlined by Olsen and Marsden (1953), i.e., eggs from virgin hens were incubated at . . .

INTRODUCTION DEVELOPMENT of a strain of Beltsville Small White (BSW) turkeys for a high incidence of parthenogenesis has been underway at this station for a number of years. Three categories of development have been recognized: 1) Membranes only, 2) Membranes and Blood, and 3) Embryos including some that survive to hatching. The incidence of parthenogenesis of all categories for all eggs tested since 1952 increased from a level of 16.7% (original stock) to a high of 46% in 1962. The percentage of well-developed embryos increased from a level of 0.2% in 1952 to a high of 13.0% in 1963 (Olsen, 1965). This increase has been attributed to two factors: (1) Selection of breeding stock on a hen family basis for a high incidence of parthenogenesis and (2) A vaccination program whereby birds are vaccinated twice yearly with fowl pox vaccine. In spite of intensive selection under these conditions (largely on…

SITUATIONS arise when it becomes desirable to maintain turkey females in laying cages rather than in pens. Such a situation arose with the discovery of parthenogenesis in 1952, after which it became increasingly important that accurate records be kept and that hens be completely isolated from males. Maintaining turkeys in batteries, however, presented problems. Our chief concern has been egg breakage in laying cages, losses which have amounted to nearly 10 percent. An improved type of floor is described here, together with results of a comparison of egg losses on this floor and on two conventional floors. MATERIALS AND METHODS * Special Floor. The improved cage floor (Fig. 1) was designed for hens of the Beltsville Small White variety, birds weighing from about ten to twelve pounds. The construction described below may thus be too light for hens of the heavier varieties or breeds, but the general features of design may …

IT IS well known that the characteristics of the shell affect the incubation and storage quality of the egg. Any improvement in egg shell quality is, therefore, an economic gain to the poultry industry. Although several investigations have been made to determine the effect of nutrition and other environmental factors on the shell, very little has been done to really understand the shell characteristics of eggs laid by the individual hen or whether or not egg shell quality can be improved by breeding. Almquist and Holst (1931) made a study of egg shell porosity by allowing an alcoholic dye solution to penetrate into the egg. Their results showed a definite relationship between porosity and weight loss during storage. They reported that egg shell porosity appeared to be nearly uniform for the eggs of a particular hen, but showed differences for different individuals. Axelsson (1932) reported the results of loss in . . .

Studies on parthenogenesis in chicken and turkey eggs have been underway at this station for a number of years. These yearly tests were conducted in order to identify exceptional individuals and superior families for subsequent use in matings in order to intensify the parthenogenetic trait. Since the original observations in 1952–1953, the percentage of parthenogenetic development of all categories has increased in Beltsville Small White (BSW) turkeys from 16.7 percent to more than 40 percent. Production of well-developed parthenogenetic embryos increased from 0.2 percent in 1952 to a high of 13 percent in 1963. Both genetic and environmental factors appear to influence the level of macroscopically observable development. It was of interest to study records of these selected hens to learn if the average percentage of parthenogenetic development, especially embryos, remained fairly constant from week to week during the testing season. MATERIALS AND METHODS Unfertilized eggs were placed each . . .

INTRODUCTION DEVELOPMENT of the germinal discs of newly laid unfertilized turkey eggs is characterized by a pronounced time lag in onset of development. The developing blastoderm of a newly laid fertilized turkey egg starts to develop soon after eggs are placed in the incubator and can be detected before the candler by 18 to 24 hours of incubation (Olsen and Marsden, 1954a). In contrast, some of the developing blastoderms of unfertilized turkey eggs first become visible at 48–72 hours, while others may require as much as 144 hours of incubation before they can be detected by candling (Olsen and Marsden 1954b; Olsen, 1965a). This present investigation was conducted to establish comparative growth curves for parthenogenetic and normal embryos. MATERIAL AND METHODS Parthenogenetic embryos employed developed in unfertilized eggs of young Beltsville Small White (BSW) and heterozygous bronze (HB) turkey hens. The HB hens were essentially Beltsville Small Whites having…

INTRODUCTION Parthenogenesis in Beltsville Small White (B.S.W.) turkeys has been developed over a period of years to a degree at which many fully developed embryos are routinely encountered each season. Parthenogenetic embryos almost invariably show a pronounced time-lag in the onset of their development, usually requiring on the average, two days longer incubation than do embryos from fertilized eggs (Olsen, 1965). Availability of parthenogenetic embryos makes it most desirable, whenever possible, to obtain comparative physiological data. PROCEDURE Twenty one parthenogenetic and 21 normal turkey embryos were used in this study. All parthenogenetic embryos had reached a stage of development at which the beak normally would have been expected to penetrate the air cell, but none had hatched. B.S.W. embryos from the same parthenogenetic strain, but obtained from fertile eggs, served as control. The live normal embryos were removed from the incubator 48 hours before the expected time of hatching in…