From my understanding bread itself is bad because the glutinous structure of it gums up the gizzard and stomach of birds. They just are not equipped to deal with it.
Now, thinking about it... it's possible that if dried, really dried, like to crouton status, and crumbled, then a small amount (say maybe 10% or less) wouldn't be entirely harmful once added to the feed and fermented. I've never seen a glutinous structure reconstitute from full on toasted status and I've played with breads for many years. The toasting seems to denature the structure of the protein.
It seems like a lot of work for a small increase in feed though. However, if you were just tossing a few things in with other things already in the oven to fully dry/toast them... maybe?
I'm sure someone else will have something more educated to say about this than me. My comments are more related to baking breads than to feeding them.
Now, thinking about it... it's possible that if dried, really dried, like to crouton status, and crumbled, then a small amount (say maybe 10% or less) wouldn't be entirely harmful once added to the feed and fermented. I've never seen a glutinous structure reconstitute from full on toasted status and I've played with breads for many years. The toasting seems to denature the structure of the protein.
It seems like a lot of work for a small increase in feed though. However, if you were just tossing a few things in with other things already in the oven to fully dry/toast them... maybe?
I'm sure someone else will have something more educated to say about this than me. My comments are more related to baking breads than to feeding them.