I have a flock that varies in ages and noticed that all of them have protruding breastbones (in various stages). They have constant food & water, have been tested for worms, have been through antibiotics (suggested by a vet to rule out infection), I've tried doing electrolyte treatments - all...
My friend and I both purchased some chicks at the fair in Litchfield ME - we ended up with a few roosters too. They are super super friendly and very pretty. If anyone is interested in a pet rooster let me know.