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Keel bone damage may be painful to birds and affect their production. In order to better understand the frequency, position, and timepoint of keel bone damage that occur during production, the integrity of W-36 laying hen keel bones housed in enriched colony cages at 748.4 cm2 (116 in2) was evaluated. At four time points, 120 birds (10 per cage; three cages per each of four rooms) had keel bones evaluated. Each hen was placed in a motion limiting restraint, scanned using computed tomography (CT), fitted in vests containing tri-axial accelerometers, and placed back in their cages for 21 d. After 21 d, the hens were rescanned and returned to their cages. This process was repeated after 133 d. The CT scans were imported into Mimics analysis software (Materialise, Plymouth, MI, USA); 3D models were made of each keel bone at each time point and exported to 3-matic analysis software (Materialise, Plymouth, MI, USA). Each laying hen's keel bone model was superimposed onto scans from multiple time points resulting in four bone pairings representative of each 21-d period, the 133-d period, and the entire duration of the project. Next, the proximal portion of each bone pairing was edited to normalize bone shape according to a strict protocol. Additionally, each pairing was divided into three portions: distal aspect (3 cm), proximal aspect (2 cm), and middle portion (remaining). Whole bone pairing and each bone portion was analyzed using the Part Comparison tool in 3-matic. Raw data were compiled into three datasets and analyzed in SAS 9.3 using the GLIMMIX procedure using a three-level random intercept model. The model controlled for time, part, part(time), and system with random intercepts of bird(cage) and cage. Overall, results revealed that the greatest morphological changes occurred during the first 21-d period with regards to time (P = 0.03) and in the distal aspect of the keel with regards to part (P < 0.0001). [ABSTRACT FROM AUTHOR]

The losses of total solids, moisture, nitrogen (N), phosphorus (P), potassium (K), carbon (C), and sulfur (S) were determined in two storage events of laying-hen manure immediately removed from three different housing systems in Iowa, USA. The three laying-hen houses were conventional cage (CC), enriched colony (EC), and aviary (AV). The houses held a nominal number of 200,000, 46,700, and 50,000 Lohmann LSL lite layers, respectively. The manure collected on belts in each house was cleaned out twice a week. A fraction of the cleaned out manure was transferred to designated storage rooms wherein losses of different components were determined in two storage events. Manure was loaded into the storage rooms over 171 days during the first storage event and over 185 days during the second storage event. The total storage periods were 202 and 245 days, respectively, for the first and second storage events. Manure was weighed, sampled, and analyzed before it was loaded into the storage rooms and at the end of each storage event. Mass balance calculations were used to determine the losses of different components. Statistical analyses show that the nutrient contents, on a wet basis, of manure loaded in CC, AV, and EC storage rooms were significantly different due to the differences in manure moisture contents. However, on a dry basis, they had no significant differences. The fresh manure cleaned out from the EC layer house was drier than that from the other two houses. Loaded-in nitrogen losses in the CC, AV, and EC storage rooms were 24.6, 12.9, and 20.8%, respectively. Nitrogen losses depended on house temperature, manure moisture, and pH. The average losses of loaded-in manure mass, moisture, and total solids during the two storage events were 27.6 ± 1.9, 33.8 ± 8.3, and 20.8 ± 7.0%, respectively. The losses of N, P, K, C, and S were 19.4 ± 13.4, 11.7 ± 5.6, 10.2 ± 6.8, 27.0 ± 6.5, and 8.3 ± 8.5% of their loaded-in amounts, respectively. The total loss of N, P, K, C, and S was 56% of the total loaded-in solids loss; thereof, the loss of N, P, and K was 7%, and C loss was 48%. The laying-hen-specific losses of N, P, K, C, and S were 0.34, 0.05, 0.08, 3.2 and 0.019 g day hen, respectively. The results of this research are important for assessing impacts of stored manure on environment and nutrient losses. They can also be used to develop methodologies for the mitigation of the emissions from egg production facilities. [ABSTRACT FROM AUTHOR]

This paper is an integral part of the special publication series that arose from the multidisciplinary and multi-institutional project of the Coalition for Sustainable Egg Supply (CSES). The CSES project involves 3 housing systems for egg production at the same research farm site in the Midwest, USA, namely, a conventional cage (CC) house, an aviary (AV) house, and an enriched colony (EC) house. The CC house (141.4 m L × 26.6 m W × 6.1 m H) had a nominal capacity of 200,000 hens (6 hens in a cage at a stocking density of 516 cm2/hen), and the cages were arranged in 10 rows, 8 tiers per cage row, with a perforated aisle walkway at 4-tier height. The AV house (154.2 m L × 21.3 m W × 3.0 m H) and the EC house (154.2 m L × 13.7 m W × 4.0 m H) each had a nominal capacity of 50,000 hens. The AV house had 6 rows of aviary colonies, and the EC house had 5 rows of 4-tier enriched colonies containing perches, nestbox, and scratch pads (60 hens per colony at a stocking density of 752 cm2/hen). The overarching goal of the CSES project, as stated in the opening article of this series, was to comprehensively evaluate the 3 egg production systems from the standpoints of animal behavior and well-being, environmental impact, egg safety and quality, food affordability, and worker health. So that all the area-specific papers would not have to repeat a detailed description of the production systems and the management practices, this paper is written to provide such a description and to be used as a common reference for the companion papers. [ABSTRACT FROM PUBLISHER]

• The structures of acceleration events experienced at the keel were described. • Acceleration events occurred mainly when hens collided with their environment. • Collisions typically occurred when hens attempted to ascend onto a perch. Factors contributing to the development of keel bone damage are not well understood. This study aimed to identify behaviors and cage structures associated with acceleration events experienced by individual hens at their keels as the birds navigated their enriched colony cage environments. Additionally, we aimed to characterize the accelerations associated with these behaviors, as we postulated that behaviors associated with higher accelerations may be more likely to lead to keel bone damage. Sixty five 19 week old Hyline W36 hens were placed in each of 12 enriched colony cages. Ten focal hens per cage were selected for observation. Each hen was fitted with a jacket which contained a tri-axial accelerometer with an external sensor that was fitted into a small pocked over the hen's keel. The logger recorded any time that the hen sustained an acceleration event at the keel (>12 G-units). Logger output was matched with video data, allowing us to describe the behavior of the affected bird at the time of the acceleration event recorded at the keel. Data on each bird were collected continuously over two 3-week periods, when the hens were between 52–60 and 74–83 weeks of age. Collisions accounted for nearly 81% of observed acceleration events with acceleration peaks of at least 20 G-units. The majority of collisions were with the perch and were sustained mainly as the hen attempted to ascend onto it. It has previously been reported that the prevalence of keel bone fractures is higher among hens housed in cages that do versus do not contain perches. This study lends support to the growing body of evidence indicating that interactions with perch contribute to the keel bone damage sustained by laying hens housed in enriched colony cage systems, however, the relationship between acceleration events and occurrence of keel bone damage has yet to be directly assessed. [ABSTRACT FROM AUTHOR]