Moldy Bread?

No, you cannot feed moldy foods to chickens. Mold is one of the few restrictions. Most molds give off toxins, and can cause serious and fatal results, such as moldy feed causing botulism poisoning. Avoid giving chickens any moldy or spoiled foods.

The problem here is that not all molds (fungi) make toxins (called "mycotoxins"). Some do, some do not.

Of the ones that do produce mycotoxins not all of them are acutely toxic meaning that they would cause immediate symptoms such as the birds becoming sick or dying soon after eating the moldy food. Some produce less acute toxins and some produce toxins that are carcinogenic or teratogenic in nature. Worse still is that some of those can be passed back to you through the eggs they lay.

MOST molds will be relatively harmless. Most. But not all. And of the ones that are not they may not produce mycotoxins that will cause immediate symptoms.

This is why mold in feed grains and milled feeds is taken seriously by the mills and all commercial livestock producers. It might only cost them a little bit of feed conversion efficiency or it might cost them everything when their animals are seriously poisoned. There's just no way to know what kind of mold it is you are dealing with. If it's moldy enough that you can see it then don't feed it to your animals.

Stale is fine but I defiantly wouldn't feed them moldy.
I give my babies basically anything I find in my fridge/cabnits that I know I won't eat but it isnt horrible yet so I tend to just give it to them

I've seen it done on a large scale, and the resulting damage was staggering. I visited a bird farm that recieved donated old bread...it was dumped into plastic trash cans and fed to the birds in an effort to save on feed. Well, the end result of feeding too much bread, and not enough chicken feed alone was enough to nearly put the farm under...then add the mold that started to grow and the bread continued to be fed. Well, the end result, a whole barn of breeding pens with sick, and dying birds. I'm sure that birds get some mold, not to mention many other things they should not eat from time to time, but why add to thier own bad choices by offering up one of your own? I say stick with air popped pop-corn(aka chicken crack) as a healthy treat. HTH

we've fed moldy bread and anything moldy to our chickens for years and years with no problems

I once lost most of my flock to mold toxins. It didn't show up as acute mold toxicity but as low immunity, i.e. they couldn't get over mild diseases. The underlying damage could only be seen in post mortem (liver discoloration etc).

Moldy bread may have safe molds or unsafe molds. You wouldn't know.

Maybe toasting the bread first would kill any harmful molds before feeding it to the chickens - maybe?

Just don't do it. Why take the chance.