Hello! Thanks again for all the feedback you're giving. As for catching escaped biters, currently the only way is by placing traps around the treadmills. And with the Advanced Treadmills the chances of them escaping gets lower. This isn't ideal though, because you'll never catch all of them, and sometimes they might start attacking another treadmill before it can run over a trap.
I don't particularly want to remove the escaping mechanic, so I think this will stay as is. If you have enough Biter Nests to get eggs from, you should always have enough caged biters though.
On second thought, a late game turret that shoots cages could work. That would mean the biters will always still escape, but you could prevent theoretically recatch 100% of them. You'll always lose some biters through the revitilaition though, but that's intended.