What can chickens eat?

Scraps are not nutritionally balanced. Letting them displace complete feed can cause nutritional disorders and lower egg production; hens that fill up on treats can run short of calcium and draw it from their bones, weakening shells.

Never feed moldy, rotten or spoiled food. Molds can produce mycotoxins (e.g., aflatoxin on corn, peanuts, nuts, rice) that harm poultry, and University of Kentucky notes mycotoxins remain even if visible mold is removed. Rotting food can also be a source of Clostridium botulinum (botulism, 'limberneck'). Stale or wilted (not moldy) produce and bread are generally considered fine.

Avoid very salty, sugary, fatty, fried or heavily processed human food (chips, fast food, candy, heavily salted leftovers). Merck notes salt above about 2% of the diet is usually considered dangerous for poultry, that birds under 21 days old are more susceptible, and that restricted water access makes salt problems worse.

Provide insoluble grit (granite grit or small stones) whenever chickens eat whole grains, scratch, seeds or forage; birds that can reach the ground usually find their own. Oyster shell is a calcium source, not grit (it is too soft). Birds eating only a complete pelleted feed do not need grit.

Chop, shred or halve large or stringy items (carrots, celery, grapes, nuts) into bite-size pieces; whole or large pieces are hard to peck apart and can cause choking or crop discomfort.

Remove uneaten fresh or wet food promptly: Chewy says not to leave it more than a few hours and never overnight; University of Kentucky says to remove scraps before they rot because rotting food attracts pests and can cause botulism.

Long, tough grass, hay, straw and other fibrous or indigestible material can cause impacted crop; keep forage short and do not feed long clippings.

Chicks: sources differ on when to start treats. Purina says wait until the first egg (about 18 weeks); Chewy's single-food pages say chicks should stay on chick starter and introduces small plain treats around 6-8 weeks; Chewy's chick-feeding guide allows treats up to ~10% of a chick's diet (mashed fruit, mealworms, scrambled egg) and adds grit if chicks eat anything besides starter and lack access to dirt.

Calcium: give layers oyster shell free choice. Your own eggshells can be fed back if dried (University of Kentucky ASC-241 says boil them, remove the membrane and crush) and broken up well so hens don't link shells with eggs.

Rodent bait: free-ranging backyard poultry can eat rodenticide bait directly (anticoagulants cause sudden death with hemorrhage; bromethalin is neurotoxic), and an anticoagulant (bromadiolone) has been detected in eggs 5-14 days after a chicken ingested it.