[header] How to prevent diseases in chickens [title] Clean your chicken's coop. [step] Every month, you should remove bedding and nesting straw or shavings and replace them with new, fresh material. Every six months, you should bleach and clean their feeders, waterers, and the entire coop. 
Cleaning the coop, feeders, and bedding material prevents mold, parasites, and ammonia from building up. It will prevent a variety of diseases, such as fungus in the chicken's feet and parasitic infections.