Feed conversion ratios in animal agriculture determine how much human-edible food is used to produce animal protein, with efficiency improvements having both economic and indirect welfare implications.
Feed efficiency and animal welfare intersect in complex ways. The high feed conversion efficiency of modern broiler chickens is achieved partly through genetic selection for extreme growth rates that cause chronic welfare problems — breast myopathy, leg weakness, and cardiovascular stress. Improvements in feed efficiency that are achieved through welfare-compromising genetics represent a false efficiency that externalizes welfare costs. Conversely, systems that prioritize animal welfare — slower-growing breeds, outdoor access, enriched environments — typically have lower feed conversion ratios, meaning more resource input per unit of protein output. The welfare-positive approach to feed efficiency focuses on achieving good production performance through health and wellbeing rather than through pushing animals to physiological limits that compromise their welfare.