In 2002 the United Egg Producers announced a new certification program that requires a significant increase in space per hen to produce eggs meeting animal welfare guidelines. Because there is little information concerning the influence of space per hen on hen performance of modern strains and increased cost associated with reduced hen numbers, this study was conducted to determine the effect of increasing space per hen on hen performance and economic returns. HyLine W36 hens (n = 1,120) were

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... rce rested at 68 wk of age and were kept in an environmentally controlled house at 3 or 4 per cage (64 or 48 in. 2 /hen). After force resting, hens were fed a commercial layer corn-soy diet containing 0.92% lysine and 1,283 kcal ME/lb (2,823 kcal ME/kg) feed for 14 wk. Average house temperature was maintained at 78°F (25.6°C), and hens were provided a 16L:8D photoperiod. Increasing space per hen increased 14-wk average feed intake (85.7 to 89.6 g; P < 0.001), egg production (73 to 75%; P < 0.05), and egg weight (61.7 to 62.4g; P < 0.05) but had no effect on egg specific gravity or mortality. Increasing space per hen improved overall feed efficiency from 3.17 to 3.11 lb (1.44 to 1.41 kg) of feed per dozen eggs (P < 0.05) and improved egg mass from 45.0 to 47.0 g/h per day (P < 0.01). Economic analysis of increasing space per hen indicated an increase in return (egg price minus feed cost) with the increase dependent upon the price spread between large, extra-large, and jumbo eggs. The significant improvement in feed efficiency would help offset some of the cost involved in increasing space per hen (hen numbers) during summer months. Results could be different for larger strains and under different environmental conditions.