There is an increasing concern about welfare issues related to battery cages, which are commonly used in Vietnam, and requires a modified cage that improves hen welfare while retaining its economic and management advantages. We combined adjacent conventional cages to form group cages to examine the effects of stocking density on egg production, economic returns, and aggressive pecking of hens. The control group included triplicate conventional cages with four birds/single cage (12 hens per three cages) or 450 cm2 area per hen. Three group cage treatments were set up with 10, 12, and 14 birds per group cage or 540, 450, and 386 cm2 of floor area per hen, respectively. Compared to 14 birds per cage, hens housed at 10 birds per group cage had a higher hen-day production, consumed less feed, and thus had a better feed conversion ratio/dozen eggs. Reducing the stocking density to 10 birds per group cage resulted in additional production cost, but it was compensated for by a high egg income, and significantly decreased aggressive pecks. Group cages benefit hen performance, profitability, and welfare when decreasing the stocking density to 10 birds per cage with 540 cm2/hen.
Keywords: Cage density; feather pecking; modified cage.