background: old laying hens are more prone to dietary calcium (ca) and phosphorus (p) deficiencies as  they absorb ca and p less efficiently than younger hens. objectives: in a 2×2 factorial design, the influence of diets with two levels of available phosphorus (ap) and phytase enzyme on the laying performance, egg quality and tibia bone characteristics of laying hens at their late 2nd producti...

This study characterizes dynamic ammonia (NH3) and carbon dioxide (CO2) emissions associated with feeding and defecation activities of laying hens. Manure handling scheme used was reflective of commercial manure-belt house operation. Four dynamic emission chambers and measurement system was developed, featuring continuous measurement of the following variables for each chamber: (a) NH3 concentr...

an experiment was carried out to compare the effects of laying hen’s diet supplemented with inorganic and different organic sources of selenium (se) on quality and oxidative stability of eggs during storage. a total of 81, (35-week old) laying hens of lohmann lsl-white were assigned to cages in a completely randomized design with 9 groups of treatment and 3 replicates of 3 birds. hens in each g...

The CO2 production rates from various animal species were measured as well as the ventilation rates (VR) in environmental rooms at Michigan State University over the course of 15 studies that considered dietary strategies to alter air emissions, including two dairy cow studies, four steer studies, two swine studies, one turkey study, four laying hen studies, and two broiler chicken studies. The...

Concerns regarding the welfare of laying hens raised in battery cages have led to the development of enriched cages that allow hens to perform natural behaviors including nesting, roosting, and scratching. This study was conducted to compare indices of production and welfare in birds housed in 2 different caging systems. Shaver White hens were housed from 21 to 61 wk in either conventional batt...

The US egg industry is exploring alternative housing systems for laying hens. However, limited published research related to cage-free aviary systems and enriched colony cages exists related to production, egg quality, and hen nutrition. The laying hen's nutritional requirements and resulting productivity are well established with the conventional cage system, but diminutive research is availab...

An experiment was performed to investigate the effect of animal vs. vegetable protein sources in the diet of laying hens on the development of hen performance. A diet containing protein sources of only vegetable origin was compared with 4 diets, each containing 1 of 4 processed animal proteins (PAP). Two PAP (Daka-58 and Sonac-60) were classified as meat meals, and the remaining 2 (Daka-40 and ...

Two thousand four hundred and ninety eggs were collected from retail markets in 6 provinces and from laying hen farms in 3 provinces. Eggs were pooled in groups of 3 to obtain 830 samples for testing. Isolation of salmonellae was made from both egg shell and egg contents. Eggs from retail markets were contaminated with salmonellae on egg shells (13.2%) and in egg contents (3.9%). Three (0.4%) s...

The influence of dietary oxidized oil was studied on laying hen performance, egg quality and blood metabolites.  Experiment was conducted on 160 laying hens (Hy-Line W-36, 54-61 wk of age) in a completely randomized design with five treatments and four replicated cages containing eight birds per cage. Dietary treatments replaced fresh soybean oil in the control diet (3% fresh soybean oil, 15.25...

the objective of this study was to evaluate the effect of cottonseed meal (csm) treated with sodium bentonite (sb) on laying hen profit and apparent digestibility of nutrients. a 3×3 factorial arrangement in a completely randomized design with 9 dietary treatments of 4 replicates consisting 3 levels of sb (0, 1 and 2%) and 3 levels of csm (0, 10 and 20%) were tested. nine mash diets were fed to...