1. Bread or any bread product: Feeding ducks bread is bad because the food has little nutritional value and can harm ducklings' growth, pollute waterways and attract rodents and other pests. Feeding bread or other high carbohydrate foods can lead to a condition called Angel wing.

2. popcorn

3. crackers

4. donuts

5. cereal

6. Certain weeds and flowers that are toxic to ducks: buttercup, daffodil, iris, lilies, lily of the valley, lupine, poppies, sweet peas and tulips. Most weeds and herbs are safe for your ducks to eat, but milkweed, pennyroyal and vetch can all be toxic.

7. Citrus fruits

8. Mangos

9. Avocados

10. Spinach: Spinach depletes the calcium in a duck's body, which can harm bones and egg laying.

11. Iceberg lettuce: it has no nutritional value and can cause diarrhea. 

12. Rhubarb or the leaves from Rhubarb

13. Eggplant

14. Green Tomatoes and the stems and leaves of tomato plants are toxic! Ducks do love tomatoes, however, only feed very ripe tomatoes on a limited basis. 

15. Raw meat

16. Raw eggs

17. Pits and seeds from apples, pears, peaches etc. 

18. Garlic and onion: Garlic and onion can affect the flavor of duck and chicken eggs, and onions can irritate the mouth and throat, and cause ulcers. Garlic is not toxic and can be helpful with respiratory issues, just remember it can affect the egg flavor. 

19. Raw potatoes and peels: Potatoes contain toxin called alkaloid solanine, which can harm birds. Sweet potato peels are, however, safe.

20. Green potatoes and tomatoes: Solanin and chaconine are toxins found in green potatoes and green tomatoes. It will cause drowsiness, paralysis,

and eventually, death. Skip any part of the potato which is green and tomatoes which are unripened. Solanin will not disappear when cooking, so just avoid it. 

21. Undercooked or dried beans: Ducks and chickens should never eat raw or dried beans. Beans contain phytohaemagglutinin, a toxin that is fatal to birds when not cooked, and kidney beans are the worst culprit. Keep any bean plants well away from your chickens and ducks.

22. Salt and salty foods: Salt can affect the bird's electrolyte and fluid balance and cause excessively wet feces, thirst, dehydration, kidney failure, and death. Food with a high salt content can also cause deformities in their eggshells over time.

23. Caffeine: Drinks containing caffeine can be toxic to birds as they can increase heart rate, induce arrhythmias and hyperactivity, and even cause cardiac arrest. 

24. Grease, greasy foods, processed foods: These foods are not even healthy for us, so why would they be for chickens and ducks? It can lead to weight gain, heart problems, and other health problems.

25. Chocolate: Never feed your ducks chocolate! Chocolate contains theobromine and caffeine, which can cause vomiting, diarrhea, increased heart rate, hyperactivity, tremors and seizures, and even cause death in your flock. You can lose your beloved bird within 24 hours of eating the chocolate.

26. Mold: The mold that grows on soft fruits, nuts, corn, and apples produces toxins known to contribute to the development of liver cancer in humans and animals. Also, ensure your flock's feed does not become damp to avoid mold growth.