all my gliders manage to burrow their way through their new hammocks and hideouts. i always have to throw them away due to this, and the thread being visible.. Any advice?

What material are the hammocks/hideouts made of?

ALL the pouches we use are 100% anti-pill fleece other then the thread.
It's two layers so the thread is on the inside. But they do manage to get threw
after awhile, but awhile is months.
Either we buy the pouches or my wife makes them.

Instead of fabric/fleece pouches make them a "nesting box" take a plastic container like a cool whip container, cut a hole in the top no smaller than 2 inches, buff the edge with a little fine grit sand paper to smooth the cut edge... cut up some fleece strips or use pompoms to put in the container and voila a comphy nesting box they cant dig or chew threw.

OR

if ya have time and crafty skills make em a coconut hut