Animal skin storage
You have to sell/donate skins to the correct vendor to use them for crafting. For the crafting in the camp, donate them to Pearson. The description will change from "donate for funds" to "donate for crafting" if it's something used for one of the crafting recipes.
There are also some crafting recipes from the Trapper that require non-legendary skins. As far as I understand you have to sell those to the Trapper to be able to craft them.