Actually no it isn't. It has no nutritional value, and only acts as filler. They won't seek the nutrition they need because they feel full, and essentially starve with a full stomach.
No. No bread is okay. The best foods are:
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)
Nut hearts or pieces (any type but without salt, coatings, or flavoring)
Frozen peas or corn (defrosted, no need to cook)
Earthworms (fishing bait or dug from the garden)
Mealworms (fresh or dried)
Chopped lettuce or other greens or salad mixes
Vegetable trimmings or peels (chopped into small pieces)
Comments
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)
Nut hearts or pieces (any type but without salt, coatings, or flavoring)
Frozen peas or corn (defrosted, no need to cook)
Earthworms (fishing bait or dug from the garden)
Mealworms (fresh or dried)
Chopped lettuce or other greens or salad mixes
Vegetable trimmings or peels (chopped into small pieces)