Many exciting and innovative laying hen-, pullet- and egg industry-related studies were presented at the 2014 Poultry Science Association Annual Meeting in Corpus Christi, Texas. Presentations focused largely on the implementation and impact of alternative hen housing systems and on use of feed additives to improve bird health and productive performance.
Enriched colonies
Alternative hen housing systems and their impact on bird health, welfare and production performance was a major research focal point at this meeting due to the increasing pressure being faced by the layer industry to convert to enriched colony cage or cage-free systems. Six bird densities (464, 581, 652, 748, 800, and 929 square centimeters per bird, corresponding to 72, 90, 101, 116, 124, 144 square inches per bird) in enriched colony cages (ECC) were investigated by M.M. Makagon et al., Purdue University and Michigan State University, using W-36 laying hens. Birds housed at 464 square centimeters per bird (72 square inches) were lighter and had more keel deformities than those in cages where more space was allowed per bird. Therefore, it was suggested that at least 581 square centimeters per bird (90 square inches) may be an appropriate space allotment in ECC systems.
T.M. Widowski et al., University of Guelph and Agriculture and Agri-Food Canada, also noted that feather condition and cleanliness was poorer for hens provided lesser versus greater space allowances per bird (520 versus 748 square centimeters per bird, respectively, or 81 versus 116 square inches) in furnished cage systems.
Scratch pads
Astroturf pads, sprinkled with feed, that are often used to encourage foraging and dust-bathing behaviors in ECC systems were found to be ineffective at reducing feather lipids or claw length by Blatchford, et al., University of California, Davis. It was also found that it was sufficient to just sprinkle feed (without the Astroturf pad) to encourage foraging and dust-bathing behaviors.
When used as a nesting material, Astroturf was also found to result in the greatest number of floor eggs, compared with straw and wood shavings, in a study done by K. Anderson et al., North Carolina State University and USDA Agricultural Research Service with 17- to 45-week-old Hy-Line Brown hens in a cage-free system. Straw was the preferred nesting material in this study.
Impact on welfare
Hen welfare in ECC, aviary, and conventional cage (CC) systems were compared by R. A. Blatchford and J.A. Mench, University of California, Davis. Hens housed in aviaries had greater keel abnormalities and dirtier feathers than in the ECC and CC systems. Patterns of feather loss also varied between systems, with aviary feather loss patterns suggestive of being due to feather pecking and those of ECC and CC likely being due to wear from the cages.
M.T. Petrik et al., University of Guelph, additionally noted that hens had lesser, but more uniform, body weights and greater incidence of keel fractures in a single-tier floor-house versus CC system.
Egg safety
R.D. Malheiros et al., U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition and North Carolina State University, also noted that 22 percent of feed samples collected from a caged environment were positive for Salmonella, whereas they was absent in the cage-free system. However, Escherichia coli were found at a greater incidence in the reproductive tract of cage-free birds compared to the caged system.
Transmission of Salmonella enteritidis was additionally compared between CC and ECC systems by R. Gast et al., USDA-ARS, Egg Safety and Quality Research Unit and North Carolina State University. This study found that the prevalence of horizontal contact transmission did not differ between these two different types of caged systems.
Many informative studies were presented at this meeting that have shed new light on key topics for the layer and egg industries. There were also numerous symposia including “The Coalition for a Sustainable Egg Supply" and “Organic Poultry Production with Natural Feed Supplements as Antimicrobials” that had many excellent presentations on layers and eggs. This research will aid in continuing to provide for optimal hen health and well-being, productive performance, egg quality and economic stability for these industries.
Feed additives
Several studies investigated various approaches to combat disease organisms and to enhance bird immunity using dietary and environmental modification strategies. Aflatoxins (toxic metabolites primarily of the molds Aspergillus flavus and Aspergillus parasiticus) in poultry feed undergoing long-term storage, up to 12 weeks, were found to be reduced by inoculation of feed with carvacrol and trans-cinnamaldehyde (at 0.4 to 1.0 percent) in a study by H. Yin et al., University of Connecticut and University of Minnesota. All concentrations of these additives resulted in aflatoxin concentrations in the feed that were less than the 20 parts per billion FDA-regulated limit, whereas untreated feed contained 30 to 40 parts per billion levels.
Another feed additive, caprylic acid, reduced Salmonella enteritidis on eggshells and in yolk (by up to approximately 44 and 32 percent, respectively) and in the cecum, liver and oviduct (by 30 to 40 percent) when included at 0.75 to 1.0 percent in the diet of 40-week-old laying hens in a study by I. Upadhyaya et al., University of Connecticut and University of Minnesota. K. Susmilch et al., California Polytechnic State University, San Luis Obispo and Quality Technology International Inc., also showed that inclusion of the prebiotic IMW50 or the probiotic Calsporin could improve hen-day egg production in 16- to 32-week-old layers’ diets, although a combination of the two additives did not further enhance production.
Valuable egg-breaking byproduct
Egg shell membranes (a byproduct of the egg industry that contain numerous proteins known to have antimicrobial properties) were investigated by S. Makkar et al., University of Arkansas and USDA/ARS, PPRSU, as a feed additive for broiler diets (0 to 2 weeks old) at 0 to 0.4 percent and were found to increase bird body weight and immunoglobulin IgM and IgY levels while decreasing corticosterone and monocyte levels.
Improved coccidiosis vaccination
K.R. Price et al., Department Pathobiology, University of Guelph, reported that covering 40 percent of pullet chick cage floors with hatch paper could enhance live Eimeria vaccine success and subsequent protection against coccidiosis due to enhanced fecal-oral transfer of vaccine progeny oocysts, regardless of whether the vaccine was administered uniformly.
