It would also seem that you're giving your guys weight bearing bones throughout the day? Those are ok for recreational chewing once every now and then but, if you've got power chewers, they can damage their teeth with them. The bone content in your dogs' meals should come from softer, easy to digest bones such as chicken carcasses (we feed half chickens minus the thighs/drumsticks...two of our guys don't digest them properly), soft pork and beef ribs, cartilage, etc. For daily recreational chewing, you can give them Kongs stuffed with cubes of raw meat and/or green
tripe (not the white bleached stuff) that's been frozen overnight. Unfortunately, we can't find raw tripe here so we use the canned Trippet brand (found at most small pet supply shops).
My pet store has Raw Green Tripe frozen in approx 2" squares and packaged in 3lbs bags. only ingredient is unbleaches,uncooked frosen fresh tripe. I'm in north eastern Ontario. The tripe is from a Alberta company called K-9 choice foods inc. maybe you can try there website for a place to buy near you www.k9choicefoods.com
on a second note, anyone know if catfish is safe raw for dogs? we catch them all the time and throw them back because we don't eat them, but if I can feed them to the dog that would be an awesome cheep way to get him a whole and fresh fish source.