Real chicken poached in plain water, cut into small bites are what my little guys love. Pixel loves it too.
There's also one kind of over the counter product called "Meaty Morsels" by Pounce. They don't appear to have BHA/BHT... Crude Protein is 30%.
The thing I like about them is they are really chewy, so I figure it's good for their teeth. They are like dehydrated meat and it says they are made from real chicken. The felines LOVE them.
I feed treats liberally but maybe I should stop that. I tend to make the kittens hunt for their treats also, spreading them out on the floor by dropping them so they spend some time looking for them.