I don't think ham is very good for dogs. It's awfully salty. I would use chicken or turkey breast...no seasoning (LOL) and like Otch says, very tiny pieces, just for the taste. I use a little mozerella cheese, but again....too much and my dogs get loose stools. So, you can mix things up. It's not good to use too much, not only because of the worry of getting overweight, but too much meat can throw off the calcium balance...and other things. But if he's really food motivated, for easier skills, you could try some of his kibble that he would have in his meal ration and for really challenging things use some real chicken...keeping in mind that when a higher value treat is used first (in a session) the lower value treat will be of even lower value. So, you might start out with the kibble and then progress to using a few tid bits of fresh meat. Sometimes it ends up that it looks like they're getting ripped off at meal time because you just can't give them too much food. But I think that dogs like to work for their food. It's just sort of "in them."