HELP! Any suggestions? All the ones that I've found are full of corn, wheat, soy, wheat gluten, and chicken. My girls can't have any of these things. When I did try some Hartz dental treats on them, they got all itchy

They were full of corn

But they DID help their breath a lot!
I brush, use petzlife, and they eat their DVP grain free kibble. WHY do they have poopy breath then?!?! And no, they do not eat their poop
There has to be a dental treat out there somewhere! I can't give them bully sticks anymore, they fight over them and plus they don't even help at all anyway.
*sigh* Perhaps I'll need to make our own dental treats somehow? I'd be willing to try that if anyone has a recipe.
TIA