RE: Are deers necks bigger only in the rut?
I would bet that the buck with the smaller neck was a younger buck or a really old buck, regardless of antler size. The big neck bucks get is a factor of several things and is actually a hypertrophy (increase in size)of the muscles of the neck. Just like a weight builder that lifts weights, part of the reason that bucks necks increase in size is that they "work out" preparing for the rut. Pushing against each other and pushing against trees. Hormones of course have a role too just like anabolic steroids that bad boy atheletes take cause their muscles to get bigger. Don't know all the mechanisms, but older bucks tend to have bigger necks. That said, it seems to go the other way when they get really old and don't get as big anymore.
The big neck is definately "meat" though. I can cut many more pounds of hamburger off the neck of a rutting buck than I can from a nonrutting one.