How many rough skinned beaver pelts can i get in a 6 cubic foot freezer?

Lots!

A lot. Roll and fold one up fur side out and they fit neatly in a plastic grocery sack. How many of those can you stack in a freezer?

Roll it up like a log?

No more like a small tight bundle. Fold the sides in to the middle then roll it up tail end to nose.

As mentioned be sure to bag the hides and space them apart so they freeze before you toss another one on top of it .
The fur is a good at insulating things even after its skinned . A second freezer is almost a good thing to just store the frozen pelts in .
I'd suggest wrapping the pelt to the nose after tieing a cord to the nose or a eye hole so it can be hung from it to help it thaw when that's needed.
Allan

For long term storage fold In the nose first since It will be the first thing to freezer burn. If the fur Is dry and It should be there Is no need to bag those hides.
The only reason you would need 2 freezers Is If the other one becomes full. Once a beaver has been skinned that un fleshed hide can lay around for days while the first layer Is being froze.
Another trick Is Is to have a section of plywood cut that will just fit In the freezer. Then you need at least 2 cement blocks. Every time you put In a fresh layer of hides place the plywood over them and then stack the blocks on top. This will compress those hides and give you a lot more room. Leave the plywood In until your ready for the next layer.

I have hauled freezers full of beaver hides home from the Carolina's for years and this works.

If i dont bag em, do i layer the freezer bottom with cardboard so the hairs don't stick?

You could do that but when you start to remove beaver to put them up once you get to that bottom layer your going to have the freezer shut down so those hides won't be stuck to the bottom.
But lining the bottom with some plastic won't hurt anything.

Thanks for replies. Had two big freezers go out, all i have is 6 cf one