By Katie Baugh and Valentina Bongiorno et.al
With cage-free housing required for laying hens producing shell eggs in Michigan and accounting for over 40% of laying hen housing in the U.S., it’s important to understand how hens interact with this type of production environment. While a variety of housing systems meet the minimum cage-free requirements of space allowance and resource provision; cage-free systems are often multi-tiered aviaries with colony nests and a litter area where hens can scratch, forage and dust bathe. Each of us has personal preferences for the layout and style of our own homes. Hens also seem to have preferences about their housing that affect their behavior and productivity, including whether they lay eggs in the litter rather than the designated nest. These preferences are shaped by hens’ biological instincts to lay eggs in protected places.
To understand how hens behave in different housing styles, we compared hens’ egg production and choice of laying location in two different cage-free aviary housing designs in the Laying Hen Facility at Michigan State University’s Poultry Teaching and Research Center.
The two cage-free aviaries used in this study had many similarities, such as three tiers, water and feed on two levels, and round perches throughout. However, they differed in a few key areas that could cause hens to behave differently. Aviary A was designed to give producers the option to enclose birds in the tiers and keep them off the litter for certain periods of the day or production cycle. As a result, hens in Aviary A could get to the litter area only from the bottom tier. The colony nest in Aviary A doesn’t have flaps along its front but is separate from more densely populated areas of the tiers for more privacy, requiring hens to navigate multiple hop platforms to the uppermost tier. The open layout of Aviary B lets hens reach the litter from any tier. Nests in Aviary B provide more space per bird, are enclosed with flaps along the front, and are located on either side of an egg belt in the middle tier. To return to the house analogy, Aviary A offers a more traditional discrete-room layout, with each room having a distinct purpose, while Aviary B provides an open plan layout free-for-all. We predicted that overall egg production would be similar between the two housing types because the hens were the same strain, from the same source and received the same feed and other management inputs. However, we predicted that hens in Aviary B would lay more of their eggs in nests as a result of the combination of nests placed closer to the ground and more nest space per hen compared to Aviary A.
Source : msu.edu