An in vivo study was conducted to evaluate pigment adsorptive ability of a natural zeolite in laying hens. This experiment was performed with three hundred sixty Hy-Line W-36 strain of laying hens at 43 weeks of age. After a two adaptation period, they received six experimental diets with a 3×2 factorial arrangement in a completely randomized design. The birds in the control group were fed a corn-soy-wheat based diet and the experimental groups were fed diets containing three levels of natural zeolite (0.0, 1.5 and 3.0%) and 2 levels of synthetic pigment (0.0 and 0.04%) for a 6-week period. Each treatment contained 60 birds, which were randomly divided into 4 replicates. The results showed that egg production, egg weight, shell thickness, and the shell percent values did not significantly differ between treatments, but that the yolk color index was significantly reduced and increased by zeolite and pigment levels, respectively.

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