Yep, that's a Eastern Diamondback. You will find them in the Southern part of Alabama and not in the Northern part as stated. It would have to be a timber that far north. That snake is probably > 4 ft in length overall. It's a healthy specimen but they are holding it out on a stick making it seem much larger than it really is.

I used to have some pictures I did with a copperhead in my yard where I took a pic of me holding the snake in my hand and then one where I was holding it out on a stick. I had some folks convinced it was the Godzilla of copperheads. In actuality it was 13 inches long and big around as a #2 pencil.