Location tracking of individual laying hens housed in aviaries with different litter substrates

The laying hen industry is phasing out conventional cages in favor of other housing systems such as the aviary - designed to improve hen welfare by providing additional space and resources including a litter area. However, we do not know whether individual hens significantly vary in the time they spend in different areas of these aviaries throughout the day, which may affect individual welfare. Further we do not know if providing different types of litter substrates affects hen use of the litter area. Using direct observations, the locations of 35 individual color -marked hens were tracked across a period of 3 days during mid lay of the production cycle. Hens were housed in 6 separate aviary pens (n = 144 hens/pen), each with one of 3 litter substrates on the open floor area (n = 2 pens/substrate: AstroTurf®, straw or wood shavings). Hens spent less time on AstroTurf® litter than on other types of litter (<i>P</i> = 0.01). Regardless of litter type, individual hens differed in time spent on litter with some hens never observed in the litter area (all <i>P</i> < 0.02). Individual hens spent different (<i>P</i> < 0.05) proportions of time in some other locations within the aviary, but these differences were not consistent across the 6 pens. No difference was seen in amount of time individual hens spent in the nest box (all <i>P</i> ≥ 0.15). These results indicate resources such as the nest box may be a fixed demand for all hens but the extent of utilization for other aviary resources depends on the individual hen. These results have implications for individual hen welfare and add to understanding of individual system-use patterns, which can inform optimal system design and management practices.