They had a few in the extreme southern part of the state near the OK border but I'm pretty sure they shot them out real quick. The CO DOW immediately passed a regulation that nobody could profit from hunting hogs to prevent landowners from releasing them to be shot for profit. This also meant outfitters can't book hunts for them. As such there was no incentive to keeping them around and they got popped pretty quickly.
That being said I'm sure there are a few that cross over the state line but not many and you can't book a hunt for them so when they are seen they are probably immediately shot by ranchers and farmers.