I've fed bread to horses without any problems. I worked where there was a deli and each day the gal would discard all left over foods. Everything from salad materials to bread, esp the ends (heals or crust, if you prefer).
I put a closeline rope across a couple of beams in the barn about head high to the horses. One was skiddish of any plastic sack whipping in the wind on a fence. I fed him a couple of pieces of bread and he ate like candy. After a few days after I fed the bread I tied the empty plastic bag onto the line. Wasn't long the bread was enjoyed and the skiddishness was gone! Did that for months because I had the bread. The geese enjoyed the bread and the lettuce.
