ORIGINAL: Uncle Bob
Deer will eat rye or almost any grass, but when you want to plant grass buy grass. Deer will eat the highest protien they can find and rye is not it in most cases. The companys that use some of it in their blends do it for a fast cover crop for the other seeds in the blend which just makes good sense. Some do it for a fast $
There is more to rye than just being a cover crop. Most things planted now won't grow or won't grow well. Rye will take off now and continue growing, providing greenfeed in the fall and early winter for deer. I find my deer sweeping my rye plot with their noses to get at it in Michigan in December. It will stop growing in the dead of winter but will be the first thing to green up in the spring. But, as others have mentioned, get winter rye, field rye farm rye (never heard it called rye-oats before) not the rye grass seed that you find being sold for lawns.