Q. for pet owners....

Also don't believe all that crap about alpha and dominance, it's BS. Please give Patricia McConnell and Victoria Stilwell a try, they really know what they're talking about.

Ditto! This has nothing whatsoever to do with dominance or the dog trying to control you. (I also have 4 rescues, and don't think it has anything to do with being a rescue, either, more likely just his personality)

Anyway, you could experiment with what he'd like in the Kong. Canned food, then frozen? I've made a weird mixture with things like yogurt, PB, dog treats, chopped carrots and then frozen. Then again, my dogs eat anything, lol.

I also agree with working on the crate training in small increments, when you're home.