I've frozen bread for later use, too, it works fine. It's just too awkwardly shaped and takes up room in my freezer, and we don't eat bread often enough to make it worth it. But it works.
Bread isn't good filler and carbs don't keep birds warm. That's a two-in-one wives' tale combo right there. Bread and other carbs are like the #1 table scrap that I will not feed to my chickens (produce and meat are okay in moderation). Excess carbs just turn to fat on the chicken's body, and...