So please do not feed your ducks: Citrus fruit. Citrus fruit can interrupt a ducks ability to absorb calcium. Spinach. Spinach is in the same boat as citrus fruit. Iceberg lettuce. If you feed them iceberg lettuce in small amounts it is okay. White Potatoes, Green Tomatoes, and Eggplant. Raw, Dried Beans. Click to see full answer. Also question is, what can ducks eat list? Good Foods for Ducks Cracked corn. Wheat, barley, or similar grains. Oats (uncooked; rolled or quick) Rice (plain white or brown, cooked or uncooked, whole or instant) Milo seed. Birdseed (any type or mix) Grapes (cut in half or quartered if very large) Secondly, can ducks eat dog food? Most pet food is grain-based anyway and the extra protein every now and then won’t hurt them. Ducks are omnivores, so some animal protein is OK as long as it won’t choke them. Similarly, why shouldnt you feed ducks bread? Bread has no nutritional value to ducks, yet it makes them feel full and takes the place of their natural balanced diet. If ducks ingest the mud while feeding, they risk catching the disease C. botulinum, which produces a neurotoxin and causes paralysis.What fruits and vegetables can ducks eat? Greens, herbs & weeds make great treats for ducks. Fruits – there are lots of fruits that your ducks will enjoy like tomatoes, chopped grapes, berries, watermelon, cantaloupe and bananas. Vegetables – fresh veggies can be fed to your ducks daily, some favorites include corn, peas, beans, cucumber, cabbage and broccoli.