HELP! Hen attacked by osprey!

One of my hens just got attacked by a big bird, i think it was an osprey. Its alive, but missing a ton of feathers, ans seems dazed. His breathing is all wheezy and he has a big lump on his chest, looks like something might have been punctured. Any ideas about what to do? How can i make him more comfortable, or any ideas on how to keep him alive. Or, if he gets any worse, how can i kill him, plesently.

Just keep him quiet and by himself away from the other birds.  Make sure water is available. He might not survive, as he probably has internal injuries. 

Best way to kill is to chop the head off with an axe. If possible you should have help with this, someone to hold the bird and someone to wield the axe.  The axe person should hold the head and gently stretch out the neck, while the bird holder holds the body still.  If done gently and the axe hit is clean, the bird will die instantly with as little pain as possible.