Re: Substitute for bone
Chicken is actually one of the less expensive meats. ?? How much are you paying? Are you getting whole chickens and cutting them up or pre-cut pieces? Pre-cut is more expensive AND more likely to be enhanced--getting whole chickens is a better idea overall.
I much prefer cornish game hen or quail over chicken for cats -- a cat isn't gonna be able to take down a chicken, so the bones are a bit big for them. They CAN eat some of the bones (rib/wing-tip, etc.) but a lot won't be consumed.
I recently found an Asian/Mexican grocery in my area. It's a bit out of the way, but fine for a once-a-month trip. I found quail - 6 processed quail for $6! When I give quail, each cat gets 1/2 (cut down the long way), at .50 a meal!
I would very much advise against using a "bone substitute." Not only do you risk unbalancing things, but cats NEED to chew through bone for dental health. Keep in mind that cats have a lower bone requirement than dogs do -- Most do best on 5% bone, 10% at the absolute outside. That is 1/2 quail or 1/4 cornish game hen 2-3 meals a week, tops. NOT much.