Does a hide have to be stretched and dyed to have It tanned?
Lets say you had 50 beaver hides that you need to have tanned. You have skinned and fleshed them. Your plan would be to drive 3 hours to the tannery and deliver them. Hides would be frozen.

Nope. Just prepare thm for how the tannery will take em.

Most tanneries do not accept green frozen hides. They do not have cold storage. It might be several months before they get to your pelts, which by then will be spoiled.

Pelts need to be stretched and dried OR salted and dried.

You should contact the tannery directly and see what their requirements are.

Beav, there are folks here that will disagree with my opinion, but after all those years as a taxidermist I believe the pelts tan up better if they are salt dried after complete clean fleshing. They always seemed to me to be more soft.....even if they are only to be wall-hangers.

A guy I trap with took a case skinned beaver with the whole tail and feet attached and unfleshed to usa foxx in Duluth, they split the tail, fleshed the hide, skinned out the feet and did a beautiful job on it. Not sure that helps answer your question but at least some tanneries take un dried fur.

I'm with J.Morse. Salt dried hides tan nicer for me. Tanneries can work with either but Molyes does prefer salt dried.

I would be nervous about how quick they can get them preserved

Sleepy Creek takes green hides, even frozen.

Sleepy Creek does a fine job.

If close, I would opt to salt the fleshed hides well and take them over. I would make contact with the business to make sure they will approve of what you are doing. I agree with others on salting after fleshing gives a better finished product. Usually the salting process takes two steps for the best job before pickling.

Going to contact Sleepy Creek on Mon. Thanks for the Info.

A salted Coyote or thinner skinned critter can be dried nicely in about a day. Hung with a fan on them 50 plus degrees air temperature or more will do it.
Beaver might take most of two days. More heat will get it done faster. Once salt dried it will be a usable skin for longer the a trapper dried one.
Salting is easy one just needs a large drip pan under the hanging skins, a fan, right heat, and a low humidity room. Clorox pool salt is a fine iodine free inexpensive salt that works if one has more then a couple of skins to salt.