Prostaglandin F (PGF) concentrations in the serum of laying and nonlaying hens and of cocks at various times during a day were measured by radioimmunoassay. The serum concentration of PGF was higher in laying hens than in nonlaying hens or cocks without regard to time of day. In all birds, the concentration showed a peak at 2 h after onset of light (0700 h). In laying hens on the day of laying ...

At present the laying hen rearing is transformed into alternative housing systems which include a deep litter system. As for the poultry nutrition, the replacement of animal protein with vegetable protein in poultry feed is applied. Therefore, in an experiment we evaluated the quality of eggs from laying hens in the cage system as compared to the deep litter system with vegetable protein substi...

The study aimed to evaluate the potential effects of feeding with phytase transgenic corn (PTC) on organ weight, serum biochemical parameters and nutrient digestibility, and to determine the fate of the transgenic DNA in laying hens. A total of 144 50-week-old laying hens were grouped randomly into 2 treatments, with 8 replicates per treatment and 9 hens per replicate. Each treatment group of h...

BACKGROUND The husbandry systems for laying hens were changed in Sweden during the years 2001 - 2004, and an increase in the number of submissions for necropsy from laying hen farms was noted. Hence, this study was initiated to compare causes of mortality in different housing systems for commercial laying hens during this change. METHODS Based on results from routine necropsies of 914 laying ...

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 ...

The goal of this study was to determine whether cell proliferation is increased in the anterior pituitary during an induced molting period in chickens. The anterior pituitaries were collected from: 1) laying hens before initiation of an induced molt (control hens), 2) molting hens 2 to 16 d after cessation of lay, and 3) second cycle laying hens 1 d after returning to lay. Pituitary cephalic an...

An experiment was conducted to evaluate the effects of different levels of mineral and vitamin premix on performance and egg traits of laying hens from 37 to 49 weeks of age. Two hundred and forty laying hens (Hy-Line W-36 strain) were randomly assigned to 5 dietary treatments of four replicates each with 12 hens per replicate). The levels of mineral and vitamin premixes in the experiment were ...

There has been growing social and scientific interest in recent years in laying hen welfare. Stress is an animal welfare parameter that has been found to alter laying hens’ physiology and social behaviour. Our study aims to test the effects of the different housing systems (laying cage, barn and free range) on the laying hens’ welfare. In this study we have taken a new approach to determine str...

The present study was carried out to determine the effects of fenugreek powder (FP) and extract (FE) on performance, egg quality, blood parameters and immune responses of laying hens. One-hundred and fifty Leghorn laying hens were used in a completely randomized design with five treatments and five replicates for eight weeks. Treatments were various levels of FP and FE including zero (control; ...