Can I rescue a battery hen?

Battery hens, or hens kept in overcrowded conditions, have a terrible life and often develop osteoporosis at an early age. Their bones go brittle for lack of exercise and also for lack of calcium, because of all their egg laying. They also have weak muscles. They may not be able to jump on the perch because of osteoporosis, or because of weak thigh or wing muscles.
If their health is not irretrievably damaged, the hens may be able to perch eventually. If not they will need straw or newspaper so that they can rest on.

Rescue hens may not live very long - three or four years as opposed to a natural lifespan of 8-10. They often can't grow adequate feathers (and so will need extra care in cold weather) and may lack disease resistance. Don't expect many eggs.