my dogs love rawhide bones.
the only problem is, if they chew on them for more than about 15 minutes, they start panting a lot, and heavily.
freyja can devour a medium sized rawhide bone in about half an hour, and gets sick in the night if i let her have the whole thing (so they dont get them if im not in the room with them).
i think that they chew on them so vigorously because they dont want the other one to get their bone.

is this panting normal?

My dog does the same exact thing. I think they are fine. My dog isn't too mobile these days. I brought water with a few ice cubes. She liked that! I think the panting comes from going after that chew hard that they are out of breath and are taking a break.

For those, who have not seen this warning about rawhides and other chewy’s.

Dogs that are chewing on Rawhides or pig ears should be monitored carefully. When rawhides or pig ears become quite soft and gooey; that is when big chunks can be torn off easily and swallowed whole.

Rawhides and / or pig ears are NOT easily digested, that is why many dog’s end up sick later. Chunks can also be lodged in the throat or cause intestinal blockage. Rawhides do come in a variety of hardness and sizes; try to pick one that your dog cannot readily devour in minutes.

Chew hooves should also be watched as they can be broken into sharp fragments, which can cause a perforation internally.

It also has been recommended that one should check the labels carefully to see where these items were manufactured, many countries use toxic preservatives. It has been recommended that rawhides made in the U.S only be purchased.

i am aware of the dangers with chunks of rawhide, and only let my dogs have them if im in the room.
i dont think even rocks are safe from freyjas chewing though
i have yet to find a toy that she hasnt gotten a hole in in under 10 minutes, and that incluedes the black kong.

My vet is so totally against rawhide..she says shes had to open more than one dog up because of the raw hide getting in a ball in their system and can't be digested. So I dont give mine any anymore even tho, she loves them..My dog loves ice...so she has lots of that