Hello. Thanks for the question.
There are a couple options here. The first, is a cage muzzle. This is what they use on racing greyhounds. They make a lot of different sizes. This allows the dog to drink and pant with the muzzle on. It should be removed when eating, though. They are nice to prevent chewing at cages or dogs that like to go outside and swallow rocks.
The other thing, and what would probably work to fix this issue, is Trazodone. This is a medication that is relatively new in veterinary medicine. It's for anxiety. In my experience, it works great to curb this anxiety driven behavior when dogs are kenneled. It's great for separation anxiety, which is likely part of what you're dealing with.
Lastly, you could seek a consult with a veterinary behaviorist. They may have some other options of tricks to use at home and then when kenneled.
Here is a nice link on how to contact a behaviorist:
I hope this helps, let me know if you have any other questions.