I have 3 chihuahua's and they all have problems. My oldest chihuahua is a male and I have taken him to the vet, changed his food to raw, eliminated chicken from his diet just in case he's allergic, he's been on apoquel, you name it, it's probably been done. He licks the air continuously after eating as if he were trying to catch flies. He has hyperpigmentation on his underbelly, is prone to yeast in his ears and between his toes and just seems depressed and anxious. I think it might be his thyroid. My 2nd chihuahua is female and every since she was a puppy, she has drank lots of water. She is obsessed with water. She continuously goes back and forth to the water bowl until it is gone and guards the water so the others can't drink.She gets some raw so she shouldn't be that thirsty. She also has been to the vet umpteen times and they can't seem to find anything wrong with her. My third chihuahua is also female and can't seem to digest raw food. If I give her freeze dried, it can't be too wet or mushy. If she is given raw or any kind of mushy food, she stands up on her back hind legs and supports herself on the arm or back of the sofa. She does this over and over again and sometimes burps up food. Sometimes I wonder if she has megaesophagus. When given kibble or dry freeze dried, she doesn't do this. I'm really frustrated and about to take them all to a new vet because the other 2 vet offices they've been to don't seem to know or care much to find out what's going on with my dogs! If anyone has any insight, please let me know!! These are the foods they've been on: Vital Essentials/Stella & Chewy's freeze dried, Freshpet Vital and Nature's Variety frozen raw. My male dog has also been on Zignature Whitefish canned.