Deer DO yard up in the winter but it is not for food, they yard up in an area that is protected from wind. Thats why they yard up in a low laying area.

The state of NH gave me maps of Deer yards in the state by my request so I can snipe coyotes. Your state will probably give you yours if you ask.

Now on to the questions at hand. I did some research and asked some people who know alot more than me. They to say the least are as amazed as I am at the thought that coyotes would "thrill kill" It is just not in their nature.

Phil, I understand that you don't can't get all the info on this happening. But without more photos and without seeing bite marks, method of killing and Etc. We just can't really say that this is the work of coyotes. As I said, I would put my $ on Wolves before coyotes.

Now, In your defense I will add this, Are coyotes bigger and badder in Maine than other places?? I have to agree with Phil to some degree.

I have hunted coyotes there, I was in Eustis and all coyotes that I called in were no more that 20-25 yards from me and 1 was no more than six feet. They all were very aware of me and my partner as each one looked right at me and the caller. It didn't matter what time of day or night, they always came in straight without winding us and without a care in the world. Coyote hunting is pretty popular in the area so it wasn't like they were not pressured.

In NH (same basic yotes) I have called them in to 10 feet during locating outings. They one that came in at 10 feet still came in even though we were standing in a small field talking and my buddy was smoking a butt.
I shined my sure fire right into the coyotes eyes and it didn't budge until it turned around and walked about 30 feet and turned towards us again.

They are less affraid than other areas.