I’m taming one of these guys now so here is how I did it: in the western approach is a spawn of these chickens, most of the times they come in couples of 2. If you have a bird, lure the one you don’t want in to the sea. Make the other one attack you while you run to your bird. quickly Fly to the top of the Rocks, stand on a place high enough to easy hit it. Shoot it until it is down (this Will take Some time) if it is down put mejoberries or kibble in it. And immediately get narcotics or bio-toxine (The ocean is very close to this place so you can get a lot of bio-toxine from the jellyfish there) then the last step is wait for a long time.