First, cottonmouths and rattlers are much more aggressive than copperheads. I have encountered all, and been chased by a cottonmouth. We have snakes on my property. We also have rats and mice. No problem for the chickens thus far, and some of them are free range, and the yard the rest are in is certainly not snake proof. I have seen a snake within a few feet of the yard. Not saying a snake will never get a chicken or egg, of course.
Second, any snake will bite if you reach for them, step on them, or similar.
Third, yes, it is illegal to kill snakes in Georgia. I don't live far from the annual Rattlesnake Roundup Festival; it's not so long ago they killed them all. Now they collect, milk, and return. If it is illegal to kill them in a state like this, it's probably illegal most everywhere.
Now, I'm not saying I haven't killed the poisonous ones in my yard, or in my house, for that matter. Yes, I've had them in and under (nesting) my house. And I actually don't even have a problem with eating them or making belts out of them. If we took game only for our own use or protection, these conversations would not even occur.
A lot of people around here can't tell a poisonous from a nonpoisonous snake, and firmly believe in killing all of them. (I can tell them apart, and I did not grow up here; we had no poisonous snakes where I grew up, or so I was told.) But anyone who kills any and all snakes just because they see them needs to read up a bit on the rat and mouse problem in Australia. There are worse things than snakes.
I don't know whether relocating a snake is illegal here or not. I don't want to know. They aren't going to come back like coons, etc. do. But I won't have a pet snake, either.