Thanks so much Eggcessive for the quick reply and the links. I'll have to do a lot of reading.
The hen made it back into the coop all by herself, ate some more and somehow flew up on the top roost. She did have a bit of a time to seat herself.
One of my hens does not seem to bend the joint where all the toes are attached to. Observing her from a couple of feet away, I could not see a wound or swelling. Hen also does not pick at the foot as if trying to remove a thorn. She did hobble to where all the other chickens hang out under...