Laying hens in aviaries with different litter substrates: Behavior across the flock cycle and feather lipid content

The tiered aviary for laying hens includes a floor litter area to promote foraging and dust bathing. Data are needed on hens' use of different litter substrates and effectiveness of substrates in removing excess feather lipids to ensure a suitable litter area. Bovans White hens were housed in commercial-style aviaries with access to one of 3 litter substrates (wood shavings, straw, or plastic turf mats-AstroTurf®, n = 4 aviary pens per substrate, 144 cage-reared hens populated per pen). Litter areas were videoed across 2 d each at 4 ages: immediately following first aviary opening (25 wk), then at 28, 50, and 68 weeks. Observations of hens throughout the d included percentages of all hens in each pen on the litter area, foraging and transitioning between the tiered enclosure and litter area. Percentages of hens dust bathing were observed from 11:00 to 15:00. Breast and back feather samples from 7 birds per pen at 28, 50, and 68 wk were analyzed for lipid content. Overall, fewer hens simultaneously accessed the AstroTurf® (P < 0.0001), but flocks showed relatively balanced transitions between the tiered enclosure and the litter area throughout the d, regardless of substrate. On average, less than 5% of all hens were observed dust bathing (peaks up to 15% of hens) with no differences among litter substrates or ages (P ≥ 0.18). On average, less than 2% of hens were observed foraging (peaks up to 4% of hens) with fewer hens foraging on AstroTurf® (P < 0.0001). Feather lipid differences among litter substrates (P < 0.0001) were inconsistent across sampling periods, possibly due to different birds sampled across time. At all ages, lipid levels were higher on the back over breast feathers (P < 0.0001) for hens housed with AstroTurf®. AstroTurf® may be suitable for nest boxes, but straw and shavings are more ideal litter substrates. Further study should investigate alternative substrates or regular substrate addition to encourage more foraging and dust bathing.