The objectives of the current study were to evaluate the effect of an acidifying diet (gypsum) combined with zeolite and slightly reduced crude protein (R) vs. a control diet (C) on nutrient retention in laying hens and compare 3 approaches to estimating nutrient excretion from hens: 1) mass balance calculation (feed nutrients - egg nutrient), 2) use of an indigestible marker with analyzed feed...

Serotonin (5-HT) regulates aggressive behavior via binding to its receptors, such as 5-HT1A and 1B, in humans and rodents. Here we investigate the heritable components of 5-HT regulation of aggressiveness in chickens, utilizing 3 distinct genetic strains. In this study, we used 2 divergently selected strains (high and low group productivity and survivability, respectively; HGPS and LGPS) and a ...

1. A total of 257 farmers with free ranging laying hens (organic and conventional) in Switzerland, France and The Netherlands with 273 flocks were interviewed to determine the relationships between the genotype of the hens, management conditions and performance. 2. Almost 20 different genotypes (brands) were present on the farms. In France, all birds were brown feathered hens laying brown egg...

This study was carried out at El Takamoly Poultry Project, Fayoum, Egypt,. A total number of 498 (450 breeder hens and 48 cocks) birds of Golden Montazah (GM) and Fayoumi (F) strains at 42 wks of age were used to evaluate the effects of two dietary levels of Se as Sel-Plex (0.1 or 0.2 mg/Kg diet) on breeder hens performance. Birds were divided randomly into 3 equal treatment groups of 83 birds ...

This study aimed to investigate the responses to abrupt changes in feeding and illumination during the egglaying period. Six hens were housed individually in cages under constant environmental conditions, with a photoperiod of 15 h (0400-1900) and ad libitum access to food for 10 days. Then the same hens were subjected to a feed withdrawal trial (between 1200 and 0830), followed by a 5-h reduct...

Sixty White Leghorn hens were assigned to 1 of 6 treatments: pretrial control (PC), full fed (FF), 9-d feed withdrawal (FW), 90% alfalfa-10% layer ration (A90), 80% alfalfa-20% layer ration (A80), and 70% alfalfa/30% layer ration (A70). For the PC, hens were killed and bones collected immediately before light restriction. The FF hens were also subjected to light restriction. After hens were fas...

Hy-Line W98, W36, and Brown hens are among the most popular strains for commercial egg production. It is of interest to evaluate the differences in performance of old hens of each variety. As part of a larger study, hens of the three varieties were maintained under production longer than 100 weeks of age and hens of each strain were randomly selected for in vitro calcium uptake (CaT) by duodena...

s of papers 47 and a mid-production period (12-16 wks of production). The SP hole distribution indicated that 85% of hens had between 21 and 100 holes. Depending on the sire, the data exhibited differences due to hen or hen by period interactions. These results indicated that eggs from hens inseminated with semen from the same sire had significantly different numbers of IPVL SP holes. This sugg...

The aim of this study was to localize macrophages in the hen oviduct and determine the effects of age and gonadal steroids on their population. Cryostat sections of oviducal tissues from immature hens (60 d of age), virgin young (175 d of age), and old (620 d of age) laying hens, and immature hens (84 d of age) treated with gonadal steroids were immunostained for macrophages. The population of ...

High prevalence of keel bone fractures in laying hens is reported in all housing systems. Keel fractures have been associated with pain and restricted mobility in hens in loose housing. The objective was to determine whether keel fractures were associated with activity of hens in furnished cages. Thirty-six pairs of LSL-Lite hens (72 weeks) were enrolled in the study. One hen with a fractured k...