I usedd to design and sew furs. It helps if you can apply a fusible interfacing, but this must be done c a r e f u l l y.
Old skins dry put and rip. To test for this, pot some spit on the skin side. Give it a moment and tug a it.
good skins will stretch, dry will rip apart. From there, you will know in which way to proceed.
the best way to cut the pelts or skins is to use a blade,exacto or razor on the skin only, the fur will sepeerate on its own, any wont have sich a mess.