A little green is nothing to worry about. The effect of green belly is often over stressed by many. Although green belly can be serious it is common on a lot of fur animals. It is not a serious defect until it turns really dark brown or black, then you will start to see some slippage of fur. I often have coyotes hanging for 2-3 days (even 5) in the shop at 40 - 60 degree F temperature with no problem. The initially frozen coyote in this picture was hung face down for 5 days and was perfectly fine re fur slippage. If you’re worried about it, wiping the area with vinegar or 3% hydrogen peroxide solution will kill the bacteria causing the rot.