Yes, 1 loaf is too much. You might want to cut down to a couple of slices each time so that you are only giving 5-6 slices a day. Even whole grain bread can change the blood sugar of swans. So, too much sugar is not good.

Try to give it lettuce, cracked corn and poultry layer pellets. It should like the cracked corn and will also pick up the poultry pellets. The poultry pellets will provide necessary nutrients such as vitamins and minerals while the cracked corn will fill the bird. Place a flat pan of cracked corn and layer pellets near your back door. Fill the pan with water so that it covers the pellets and corn and then place the bread on top of the water. The swan should begin to eat the rest of the food. Let us know how this works. Also, what is the color of the beak?? This will give us an idea of what species the bird is as well as age (juvenile/adult). Thanks for your question. The Regal Swan