Effects of different litter substrates and induced molt on production performance and welfare quality parameters of white Leghorn hens housed in multi-tiered aviary system.

Authors: REGMI, PRAFULLA - Purdue University; ROBINSON, CARA - Michigan State University; Jones, Deana; Gast, Richard; TEMPELMAN, R. - Michigan State University; KARCHER, DARRIN - Purdue University

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2018
Publication Date: 11/1/2018
Citation: Regmi, P., Robinson, C., Jones, D.R., Gast, R.K., Tempelman, R.J., Karcher, D.M. 2018. Effects of different litter substrates and induced molt on production performance and welfare quality parameters of white Leghorn hens housed in multi-tiered aviary system. Poultry Science. 97:3397-3404.

Interpretive Summary: Dramatic pledges for selling/using eggs from cage-free housing systems by 2025 have been made by many US retails and food manufacturers. The cage-free pledges have necessitated a rapid shift in hen housing systems. Understanding the implications of management practices such as induced molting and litter management in cage-free housing systems on production parameters and laying hen welfare quality are integral to a successful transition to cage-free egg production. A study was undertaken to compare litter substrate (bare cement, astroturf, wood shavings, and straw) and induced molting in a cage-free aviary housing system throughout a complete flock life cycle. After thorough examination of egg production and welfare quality parameters, it was determined that litter substrate in cage-free aviary housing does not impact egg production parameters or the physical assessments of hen welfare quality. Furthermore, inducted molting can be successfully conducted in cage-free aviary housing.

Technical Abstract: More than 90% of the commercial egg production in the United States is pledged to be in cage-free systems by 2025. Management practices like induced molting and litter area management have come under scrutiny because of the housing system change. The aim of this study was to determine the welfare and production implications of different litter substrates and also evaluate induced molting of hens in a cage-free system. Bovan White hens were housed in a multi-tier aviary system with daily access to open litter area of either Astroturf® (AT), wood shavings (SH), or straw (ST) and bare concrete floor (CO) serving as control. At 68 wk of age, molt was induced in half of the hens whereas the other half continued without molting to 116 wk. Production and welfare parameters were measured periodically throughout first and second cycles. Litter substrate did not influence hen-day production and case-weight measurements. However, CO had the lowest total number of eggs produced during the first cycle (P < 0.05). Hen-day percentage was ~ 14% greater in molted hens during the second cycle with egg case-weight being heavier in non-molt hens towards the end of second cycle (P < 0.05). The only welfare parameter influenced by litter substrate during the first cycle was a greater crop feather loss in AT than ST at mid-lay (P < 0.05). Keel deformations increased with age irrespective of the litter substrate with 91.5 % of palpated hens having keel deformations at the end of first cycle (P < 0.05). Molting did not influence the keel palpation and footpad scores whereas frequency of moderate comb wound was greater in molt hens during molt (P < 0.05). Severe feather loss was seen in non-molt hens during the second cycle (P < 0.05). Litter substrate does not affect production and physical parameters of welfare of hens in a multi-tier aviary system. Additionally, induced molting can be successfully carried out in the multi-tier cage-free system.