#1 is too dark without enough contrast between the subject and background. #2 is good but has too much distance between brett and the deer... colors are great. #3 Looks like the deer is growing out of his stomach... like a scene from "Alien." #4 Has the best balance, tone and contrast though there is a bit of light/angle issue but it should be okay.
I like number 4 because you can really see the character in the deer. All of them are great pics though.
I like #4 the best. I think it has the best view of the buck with a nice clear blue background. I like #1 aswell it has better lighting but I think the backdrop behind them with the wall takes away from the subjects just a little bit to much. My vote is for #4 with a second place #1. Great buck BTW. Congrats to him