An experiment was conducted to study the effect of broiler breeder feeding management practices on pullet performance, BW uniformity, and carcass traits during rearing (to 22 wk of age). At 3 wk of age, 1,200 Ross 308 breeder pullets were assigned to one of 5 treatments: 1) control: standard mash diet, fed daily; 2) high fiber: mash diet containing 25% lower nutrient density, fed daily; 3) scatter: standard diet in pellet form scattered on litter, fed daily; 4) skip-a-day: standard mash diet, fed on alternate days; or 5) grading: standard mash diet, fed daily (birds sorted into low, average, and high BW groups every 4 wk). Birds on the high fiber treatment consumed more feed (P<0.0001) and had the highest feed conversion ratio (FCR; P<0.004) but the lowest ME to gain and CP to gain ratios (P≤0.002). Skip-a-day treatment pullets consumed more ME and CP than birds in any other treatment (P<0.001). Grading yielded the highest BW uniformity at 22 wk of age (CV=6.2%), while control and high fiber treatment groups were least uniform (CV>15%; P<0.0001). Skip-a-day feed restriction produced birds with the significantly lowest breast muscle and highest liver weight compared to all other treatments (P<0.05). Variation in shank length, chest width, and breast muscle was lowest in the grading treatment, whereas the CV for fat pad and liver was lowest in the skip-a-day treatment. In this trial, broiler breeder target BW profiles were achieved using combinations of quantitative and qualitative feed restriction, or preemptive management practices. Qualitative diet dilution and skip-a-day management did little to increase flock uniformity relative to the control during the most intense period of feed restriction (7 to 19 wk). Scatter feeding increased flock uniformity to a small degree, whereas grading yielded the highest increase in BW and carcass trait uniformity.

Hens were fed corn-soybean meal diets containing 0.35, 0.25, 0.15, or 0.10% nonphytate phosphorus (NPP) (40 to 60 wk). Phytases A and B were added at 0.25, 0.15, and 0.10% at 250 to 300 units of phytase (FTU)/kg feed in a 3 x 3 factorial; 0.35% was a control diet. Treatments were replicated with eight cages per treatment (five hens per cage) in a randomized complete block design. Phytase supplementation had a significant effect on several production parameters: feed intake, feed conversion, and egg mass. Results showed nonsignificant effects (P < 0.06) on feed intake when hens were supplemented with phytase A or B and consumed more feed compared to the basal diet at 0.10% NPP. The feed conversion of birds fed 0.10% NPP without phytase was the least efficient compared to the other nine treatments (P < 0.05). Egg mass was significantly greater for hens supplemented with phytases A and B than for hens fed the basal diet at low (0.10%) NPP (P < 0.05). There were no significant differences in egg production, egg weight, specific gravity, Haugh units, wet shell, or dry yolk percentages. Dry shell percentage was higher among basal diets at 0.15 and 0.25% NPP in contrast to phytase, whereas albumen and dry yolk percentages were significantly higher for diets with phytase than for the basal diet at 0.10% NPP. Bone ash percentage was uncharacteristically high in hens fed 0.10% NPP without phytase; however, mortality was 22% in this group. Phytase supplementation improved Ca and P digestibilities to varying degrees. Supplementation of phytase in normal, corn-soybean meal diets improved feed intake, feed conversion, and egg mass and elicited a response in shell quality and egg components at the low (0.10%) NPP.

A study was conducted to assess the effects of varying cage spaces on a commercial laying hen strain fed differing levels of dietary metabolizable energy (ME) for 15 wk. Four cage space allowances (342, 413, 516, and 690 cm2/hen) were combined with 3 levels of dietary ME (2,800, 2,850, and 2,900 kcal of ME/kg) in a 4 x 3 factorial arrangement. Each treatment was assigned to 6 replicate cages for a total of 72 cages in randomized complete block design. Feed intake and metabolizable energy intake were significantly (P < 0.01) greater for hens housed at 690 cm2/hen compared with those housed at 413 and 342 cm2/hen, but not those housed at 516 cm2/hen, across all dietary ME levels. Egg production and egg mass were significantly (P < 0.001) improved for hens housed at 690 cm2/ hen in contrast to other cage spaces and across all energy levels. There were no interaction effects of ME levels on laying hen performance at varying cage space except for body weight change. Hens housed at 516 cm2/ hen and fed 2,800 kcal of ME/kg exhibited the greatest weight change, which was significantly (P < 0.05) greater than those fed other levels of ME at the same cage space. Hens housed at 690 cm2/hen had significantly (P < 0.05) greater ME efficiency of egg production than hens housed at other cage spaces. Hens fed the diet with 2,900 kcal of ME/kg had significantly (P < 0.001) greater ME digestibility compared with those fed 2,800 or 2,580 kcal of ME/ kg with differences of 107 and 118 kcal of ME/kg, respectively. There were no significant effects of ME levels observed except ME digestibility, and no significant effects of cage space allowance on egg weight, hen weight, bone ash, or maintenance energy intake. It is evident that decreasing the number of birds per cage and increasing cage space allowance per hen had an overall positive effect on performance.

A total of 400 one-day-old, straight-run, commercial (Ross 308) broiler chicks were used to evaluate the effects of two dietary levels of zinc (Zn) sources on broiler chick performance, carcass traits and blood parameters. Corn-soybean diets were formulated for three rearing phases (starter, grower and finisher). The two dietary treatments applied consisted of the addition per kg of diet of 80mg of inorganic Zn (ZnO) (T1), or 80mg of ZnO plus 42mg of an organic Zn-amino acid complex (Availa-Zn120; Zinpro Corporation, Eden Prairie, MN, USA), totaling 122mg of the combined organic and inorganic Zn sources (T2). Birds were distributed according to a completely randomized design in the two treatments with eight replicates (pens) of 25 birds each. Feed and water were provided ad libitum. On day 42, blood samples were taken from four birds closest to the group average weight per replicate (32 per treatment) and then slaughtered for carcass evaluation. The results of this study did not find any significant effect of either of the evaluated Zn sources on broiler growth performance. Mortality rate was significantly lower (p<0.05) by the higher Zn concentration and the Zn sources group (T2). Carcass yields were not significantly influenced by the treatments. Breast quality showed significant improvement (p<0.05) in shear force (T2), indicating juicier meat. Higher concentrations (p<0.05) of Zn, Phosphorus (P), and total protein in blood were noted in (T2). Birds fed a mixture of organic and inorganic Zn source (T2) presented overall better results.

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