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Achieving high lifetime productivity with broiler breeder flocks is challenging because feed restriction intensity continues to increase due to selection for efficient, fast growing, and high yielding broilers. Flock uniformity is compromised by intense competition for limited feed. Equitable feed allocation and stable metabolic rates are likely to increase reproductive efficiency. A prototype precision feeding (PF) station was developed to sequentially feed birds according to their individual needs. If pullets were under target BW, the station provided small amounts of feed during short feeding bouts. The objectives of the current study were to determine whether a sequential PF system could control BW of individual group-housed pullets by matching real-time BW to BW targets, and to quantify fluctuations in metabolic rate using continuous or stepwise increases in target BW. Two treatments were used in a completely randomized design: CON, the Ross 708 target BW curve interpolated hourly; and STEP, the Ross 708 BW curve updated every 21 days. Twenty Ross 708 broiler breeder pullets were assigned to the treatments (n = 10 per treatment). All pullets were fed by one PF station in a single pen from 35 to 140 d of age. Feed intake and BW records were used to evaluate BW and BW variation to estimate maintenance ME requirements, and to evaluate feeding patterns. Differences were reported as significant where P < 0.05. Precision feeding allowed different feeding programs to be evaluated in the same pen. In both treatments, BW CV decreased to less than 2% by wk 20. Complex temporal differences in feed intake and BW reflected treatment-specific target growth trajectories. Metabolic rate in the STEP treatment increased 70 to 100% during wk in which rapid growth was permitted, compared with wk in which BW targets were held constant. Precision feeding shows promise both as a data acquisition system for poultry researchers and breeders, and as a means of increasing broiler breeder flock uniformity., (© 2017 Poultry Science Association Inc.)

With increasing disparity between broiler breeder target weights and broiler growth potential, maintenance energy requirements have become a larger proportion of total broiler breeder energy intake. Because energy is partitioned to growth and egg production at a lower priority than maintenance, accurate prediction of maintenance energy requirements is important for practical broiler breeder feed allocation decisions. Environmental temperature affects the maintenance energy requirement by changing rate of heat loss to the environment. In the ME system, heat production (energy lost) is part of the maintenance requirement (ME). In the current study, a nonlinear mixed model was derived to predict ME partitioning of broiler breeder hens under varied temperature conditions. At 21 wk of age, 192 Ross 708 hens were individually caged within 6 controlled environmental chambers. From 25 to 41 wk, 4 temperature treatments (15°C, 19°C, 23°C, and 27°C) were randomly assigned to the chambers for 2-week periods. Half of the birds in each chamber were fed a high-energy (HE; 2,912 kcal/kg) diet, and half were fed a low-energy (LE; 2,790 kcal/kg) diet. The nonlinear mixed regression model included a normally distributed random term representing individual hen maintenance, a quadratic response to environmental temperature, and linear ADG and egg mass (EM) coefficients. The model assumed that energy requirements for BW gain and egg production were not influenced by environmental temperature because hens were homeothermic, and the cellular processes for associated biochemical processes occurred within a controlled narrow core body temperature range. Residual feed intake (RFI) and residual ME (RME) were used to estimate efficiency. A quadratic effect of environmental temperature on broiler breeder MEm was predicted ( < 0.0001), with a minimum energy expenditure at 24.3°C. Predicted ME at 21°C was 92.5 kcal/kg; requirements for gain and EM were 2.126 and 1.789 kcal/g, respectively ( < 0.0001). Birds fed the HE diet were more efficient, with a lower RME than birds on the LE diet (-0.63 vs. 0.63 kcal/kg), translating to ME of 135.2 and 136.5 kcal/kg, respectively. In the current experiment, optimal biological efficiency was predicted at 24.3°C in feed-restricted broiler breeders fed the HE diet.