My guineas sleep in the coop with the chickens at night except in summer. They have chosen a tree over the turkey pen and sleep in it under the canopy of leaves where they are unoticed. But they don't start sleeping there until the tree is full and they feel safe. I've had excellent luck with them and have only lost females who chose to nest out in remote tree lines where they got taken by coyotes. They can in fact be trained to sleep inside but it takes time.
And yes they are stupid. They will run back and forth and go crazy if they are in a two foot high fence when it's obvious they can just fly out.
And yes they are stupid. They will run back and forth and go crazy if they are in a two foot high fence when it's obvious they can just fly out.