Study shows better feed conversion, immune response in caged hens

Dr. Ken Anderson of the North Carolina State University poultry science department recently presented results from a comparison of brown-strain hens reared and housed in cages or on range.
In the case of the non-confined pullets, rearing through 12 weeks was completed in litter pens followed by movement to range. Performance was monitored from 17 to 82 weeks of age. Pullets reared in cages were 93 grams heavier than pullets reared on range. There was a 13% reduction in feed consumed by range pullets consistent with body weight and supplementation from foliage. Caged hens showed significantly higher feed conversion efficiency and egg mass. There was no significant difference in egg weight or size. Caged hens produced 90% grade A eggs, compared with 86% for the range hens, although there was no difference in the number of checks between the housing systems.
There were no differences in cholesterol content of eggs and both vitamin A and E levels were similar. Eggs from the range-housed hens had higher total fat and, correspondingly, both monounsaturated fat and polyunsaturated fat levels compared to caged hens. There was a numerical but nutritionally insignificant difference in omega-3 content of eggs (0.13%). Beta-carotene levels were higher in the range-housed hens compared to the caged hens, although this difference could be compensated for by supplementation with commercially available xanthopyll supplements.
The immune response of range-housed hens was lower than their counterparts in cages. This was determined by antibody tier following Newcastle disease vaccination.