Maybe your pup just doesn't like those foods?? They'll tell you when they don't like something or if it makes them sick. Just a thought, my yorkie had been on a prescription diet for quite awhile, and we ran out of food, so we bought a new bag of it...He refused to touch it...We were baffled, as he always ate his food. So we checked the bag, and it had expired two months before. The food was bad and he did not want it. Dogs are very smart. Try feeding him a higher quality kibble and maybe he'll eat that. Also you can try to mix in some chicken or a little cottage cheese. Dog usually love that
Or some canned Merricks or Evangers... Good luck!!