Thanks for the replies.
The raccoons had not been dead long when I discovered them Sunday afternoon -- they had not yet attracted flies.
I am now thinking the raccoons died of poisoning.
Two raccoons dying of rabies at the same time and place seems too much of a coincidence. I didn't inspect the remains closely, but I did not see any blood from gunshot wounds. The field is close enough to my farmhouse for me to have heard any shooting. I know that my two nearest neighbors haven't been using poison, but I have noticed that several dogs I used to see down the road have disappeared in the last month or so.
Does anyone know the "typical" range of travel of raccoons?
Steve