We have fed cygnets small amounts of canned corn when cracked corn was not available. Even in small amounts, the canned corn caused diarrhea in the birds. The salt content is not that great for them either. In a pinch, the corn can be used in very small amounts. Washing the corn so that some of the topical salt can be removed should be conducted, but the best form is fine cracked corn. The corn acts as a filler as well as provides much needed Vitamin A. Without this nutrient, the birds' can develop nutritional deficiencies possibly resulting in neurological problems. The dried cracked corn tends to stay in their system a little longer which allows maximum nutrient absorption. The Regal Swan