Study of the utilization of light egg-type males: a proposal for the sustainability of the egg industry.

This study evaluated the performance and viability of light egg-type males, usually euthanized at the hatcheries, from White and Brown Leghorn laying hen lines. One-day-old male chicks, half from each hen line, were raised in floor pens until they were 42 d of age. The birds were distributed into 48 floor pens, furnished with tube feeders and nipple drinkers, and submitted to 24 h of continuous light, 3 feeding phases (1-7, 8-21, and 22-42 d) and diets composed of corn and soybean meal as the main ingredients.

Comparison of the effect of different methods of molt: production and welfare evaluation.

The purpose of this study was to evaluate alternative molting protocols assessing hen welfare and performance during and after molt. Hyline W-36 pullets were housed at 15 wk of age, and their egg production was obtained during this first cycle. When birds were 80 wk, the following molting treatments were applied: a conventional molt consisting of 10 d of fasting followed by cracked corn for 8 d and a pullet developer diet for 10 d; and 4 alternative molting programs: a soy hulls-based diet (12% CP, 1,455 kcal/kg of ME, and 1.

The effect of pre- and postmolt diets high in n-3 fatty acids and molt programs on skeletal integrity and insulin-like growth factor-I of White Leghorns.

This study investigated changes in bone integrity and circulating concentrations of insulin-like growth factor-I (IGF-I) of hens subjected to 2 distinct molting regimens and fed pre- and postmolt diets high in n-3 or n-6 fatty acids. A dual-energy x-ray absorptiometer determined bone mineral density (BMD) of the tibia and humerus of 45 live hens from 62 to 76 wk of age. Densitometric scans were also conducted in excised tibia and humerus at 66, 71, and 76 wk of age.

The effect of an induced molt using a nonfasting program on bone mineralization of white leghorns.

To determine changes in bone mineralization during molt, 66-wk-old White Leghorns were assigned to either a fasted molting regimen using feed removal for 10 d, followed by the ad libitum consumption of cracked corn for 7 d and a pullet developer diet for 10 d or a nonfasted molting regimen lasting 27 d that included the ad libitum consumption of a diet containing 71% wheat middlings and 23% corn. Both molting regimens restricted light to 8 h/d, and water was provided ad libitum. At 28 d postmolt, hens from both molting treatments were returned to a regular egg-laying diet and 16 h/d of photoperiod.

The effect of an induced molt and a second cycle of lay on skeletal integrity of White Leghorns.

The effect of an induced molt and a second egg laying cycle on White Leghorns hen's skeletal integrity was investigated in a series of 3 experiments. Using dual-energy X-ray absorptiometry, bone mineral density (BMD) and bone mineral content (BMC) of the left tibia and humerus were measured in live hens and excised bones and correlated with invasive bone measurement tests, egg traits, and the incidence of broken bones in carcasses of processed hens. The results of all 3 experiments showed that an induced molt was detrimental to skeletal integrity.