You are right about Rawhide not being healthy. And, like others have said, bully sticks should only be used when you are supervising your baby.
We have used RW balls with the holes in them for Lucas. We have the yellow football-shaped one:
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We use it only for when he is in his kennel and we are out, so he associates it with us leaving and happily hops into his kennel whenever he sees it. We put a half or 2 halves of a square soft treat inside it which occupies him as he tries to get the treat out. The treats we normally use are:
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