I've inspected the pen with new eyes (the same eyes that saw this big bobcat starting insolently at me). I am satisfied that the fence is secure, since it's 2x4" wire covered with hardware cloth. I am satisfied that nothing can dig under, since the hardware cloth is trenched into the ground and set in concrete, except at the gate, where the gate rests on concrete pavers. The back fenceline that borders the woods/underbrush does not have a top rail, so something would have to jump onto the top of the wire fence.... from a crowded launch point in the brush. The two long sides have a 2x4 wooden top rail, so something could jump up onto it, or clear over it-- into the aviary netting. I think the aviary netting would hold for something 20# but not 50# and I am purely guessing on that. I'm not sure how to test that theory other than throw things over the fence and see what happens LOL. But I'm reasonably satisfied with security of the pen.
That said, I did see cat footprints in the tack room of my barn this morning. I really thing it's the housecat that has been sighted in the neighborhood. But if it's a bobcat I think it's a much smaller one that the one I saw. Sure got my adrenaline going though!
If I can find a great price on stronger netting for the top, I will add another layer of netting. It's not a great time to invest another 300-500 in the chickens right now, so I will have to shop it.
I did check on those links for trapping/hunting licenses. From what I can tell you only need them if you are trapping/hunting with intent to sell the fur. I would not be selling fur, just protecting my chickens.