White rock chickens are the industry standard but weight gain is usually lower on pasture than in conventional settings. Feeding them probiotics, therefore, might improve the health and weight gain of pasture-raised chickens. With several products on the market, Justin wanted to see if any would have a real effect on his chickens. Justin set out to compare three commercial poultry probiotics to see if they increased growth rates and survival of pasture-raised White Rock chickens.