The most common housing system for egg-laying hens is the conventional cage, which houses multiple birds in a wire cage at a high stocking density. Hens have access to food and water but very limited opportunities to perform other highly motivated behaviors, such as nesting. As a result of concerns about behavioral restriction, the egg industry is now considering adoption of furnished (enriched) colony cages which contain perches, a scratch pad to facilitate foraging and dust bathing behavior, and a nest box. It has been suggested that allowing animals to perform natural behaviors, like nesting, improves their welfare by decreasing negative affective states like frustration. It is important to assess the desirability of the nest sites that are being incorporated into new housing systems in order to ensure that the nests are serving their purpose in satisfying the hens' needs to perform nesting activities. In my two experiments I examined egg laying locations of White Leghorn hens given a variety of nest floor substrates and nest enclosure. I hypothesized that hens would prefer highly friable substrates over the wire cage floor, and enclosed nests. Previous observations indicate that friable substrates that are able to be moved and manipulated by the beak and body of the hen are preferred to rigid nest materials. In experiment 1, I examined hens' preferences for sand, Astroturf and Astroturf with feed as nest flooring in open nests consisting of a shallow wooden frame. The hens did not prefer friable substrates, possibly because the nesting area was not enclosed. In experiment 2, each nest substrate (wood shavings, foam pad, wire or Astroturf) was either again open or surrounded by opaque plastic curtains. The hens showed a clear preference for enclosure, as predicted, however, there was no preference for any combination of nest enclosure and substrate. Together these studies provide evidence that nest enclosure is important for motivating hens to lay within a given nest, but that hens laid as readily on the wire cage floor as any of the other substrates provided. These studies provide insight into the components that need to be incorporated into the design of nests in furnished cages.
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