Sodium bentonite can bind to dietary pigment and decreases yolk color scale. Sodium bentonite is one of the main parts of Formycine® Gold, the effect of different levels of Formycine® Gold and dietary pigment on egg quality, egg yolk color and performance criteria of laying hens from 26 to 34 week of age were stud-ied. One hundred ninety two Hy-Line hens were divided into 24 groups of 8 birds each and randomly as-signed to 6 dietary treatments of 4 replicates each. The study was conducted in a completely randomized design with a 2 × 3 factorial arrangement of treatments based on 2 levels of pigment (0 and 0.4 g/kg) and 3 levels of Formycine® Gold (0, 1 and 2 g/kg). Feed intake, body weight, feed to egg ratio and egg produc-tions were recorded at the end of the weeks 28, 30, 32 and 34. Egg quality characteristics including egg weight, specific gravity, yolk color scale, egg shell percentage and thickness were evaluated every other week. Formycine® Gold and dietary pigment had no effect on performance for entire of the experiment. Egg shell weight and thickness increased by 0.4 g/kg dietary pigment at 29-30 weeks of age. Hen-day egg production was not influenced by dietary treatments. Egg specific gravity was similar in hens fed different levels of Formycine® Gold and pigment, except for 29-30 weeks of age. Regardless of Formycine® Gold levels, diet supplemented with pigment considerably increased yolk color scale. It seems that, by decreasing the amount of sodium bentonite in Formycine® Gold, it can be used without any adverse effect on egg quality, egg pigmentation and performance of laying hens.

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