What can chickens eat?

Avocado (especially the skin and pit), chocolate, raw and dried beans, rhubarb, coffee grounds and other caffeinated products, and moldy food. If your hen ate something toxic or seems unwell, call your vet – the RSPCA says to always contact a vet if you’re concerned. Keep a sample of the feed (Merck Veterinary Manual).

A good-quality commercial feed is the basis (RSPCA Australia), and the RSPCA recommends a complete feed rather than a mixed one. Hens without worms, insects and plants to forage should get a complete layer feed as their basis, says the German veterinary association for animal welfare (TVT). Treat scraps like a treat, not the main course (UC Cooperative Extension): other products dilute the nutrients in the commercial feed (University of Maine).

Scratch, grains and kitchen scraps together should make up no more than 10 percent of the daily diet (Oklahoma State, RSPCA Australia); the British Hen Welfare Trust is stricter at no more than 5 percent. Oregon State puts grains at about 10 to 15 percent and suggests no more than your hens can clean up in about 20 minutes. Even too many healthy treats can cause issues (British Hen Welfare Trust): Penn State Extension says table scraps and whole grains can decrease egg production, make hens fat and cause prolapse.

Greens help keep egg yolks a deep orange (Oregon State), and the University of Maryland says chickens can get 5 to 20 percent of their feed by grazing. Without a lawn, Switzerland’s Federal Food Safety and Veterinary Office (BLV) suggests lettuce leaves and short blades of grass. Scatter food around the run and yard so your hens can forage for it (RSPCA Australia).

Laying hens should have oyster shell free choice in a separate feeder (Penn State Extension); oyster shell provides extra calcium (RSPCA). They also need insoluble grit, such as hard flint grit (RSPCA).

In the UK, it’s illegal to feed kitchen scraps to chickens, even pet hens (RSPCA, APHA) – only fruit and vegetables that never entered your kitchen are allowed (DEFRA). In the US, extension services allow small amounts of table scraps, up to 10 percent of the daily diet (Oklahoma State); UF/IFAS Extension says to avoid fatty, salty, sugary or rotten foods. In the EU, Germany’s agriculture ministry (BMLEH) says kitchen and food waste must not be fed to laying hens.

Free-ranging backyard chickens may accidentally eat rodent bait (Merck Veterinary Manual), and they readily eat poisoned rodents and insects (RSPCA Australia). Some garden plants may be poisonous to chickens, too (RSPCA Australia).

Common signs of toxic plant poisoning include weight loss, diarrhea, lethargy, fewer eggs and increased mortality (UF/IFAS Extension). If an illness occurs, have a vet find the cause (German veterinary association for animal welfare, TVT). If your hen ate something toxic or seems unwell, call your vet – the RSPCA says to always contact a vet if you’re concerned. Keep a sample of the feed (Merck Veterinary Manual).

Then we rate it more cautiously and say so. Avocado, for example: UF/IFAS Extension, UC Cooperative Extension and RSPCA Australia advise against it, while a Colorado State guide considers the flesh fine – we rate it “Toxic.” For tomatoes, bread, potatoes, onions, eggshells, cheese and meat, at least one source advises against them (“Better not”). Most sources allow corn, oats and watermelon in small amounts, but some advise against them (“Only a little”). And for treats, the British Hen Welfare Trust says no more than 5 percent, other sources 10 percent.