It appears to me a single layer will also entangle snakes. They push head through a hole and keep going through till body stretches opening stopping forward movement, then scales get hung when snake tries to back out catching snake. I have real problem in pond setting where water snakes and their kin get hung up as well.C, are the critters getting stuck in it because you doubled it up? Maybe a single layer, stretched better, would be safer.
Snakes will get through anything with small enough openings.