I have 2 coyotes and 3 coons that when I put them in salt water, they have not rehydrated. They have been in there for 36hrs and the skin is still tough. I am worried if I keep them in there any longer there is going to be hair slippage. What am I doing wrong? These were skinned, fleshed then boarded by the trapper. The other hides that were with them all hydrated, just these are not.