Where I live, it's the wolves and the foxes. Once they know there's something to eat, they just keep on coming back. However, my dog will alert me to these animals. Hawks and falcons, on the other hand, come in unnoticed by the dog and swoop down and grab- then leave. We lost a young cockerel to a Gyrfalcon a couple weeks back and I only knew something was going on when the chickens all made a ruckus until I came out there- and they got very quiet. I spent about 10 minutes looking into the woods before I spotted it eating my cockerel (alive) on the ground. Horrible.
raccoons... for the reason that they keep coming back once they have a successful strike. I had to pack a lot of fence repair into the 2-3 hours of daylight I had after work the day after a strike because I knew it would come back for more hens. Very maddening.
I did note Hawk wasn't up there. Neither is snake. But my main problems are raccoons and a fox.
Although the latest "predator" I haven't yet identified, it could EASILY be a raccoon or fox. Probably a raccoon. Something reached through the chain-link and grabbed eggs from a nest box that was sitting right beside it. Foxes can use their paws to pull something forward like that. And racoons have "thumbs" like we do, so they are definitely capable of it.
I used to have a problem with a king snake that got in and tried eating eggs and baby chicks. But after getting himself stuck inside of the pen because he swallowed a GOLF BALL (fake egg for the hens), we were able to catch him and kill him. No problems with him since then!
hawk!! and yes they are protected,grr. we have a pair of them, have a loose web over my run. I just walked to my kitchen sink and sure enough one tried it,chickens gone nuts, feathers flying and it didn't get one, d#@$hawk perched on my clothes line post till I got out there in 22 degrees n a T-shirt too. one back giant was down I checked her some she kinda flighty at the moment, but no blood I can see,but she got back up and started scratching after 5 minutes. putting more rope over run later, off to tsc and Lowes I go.