I would assume that the deer will move to your cowpea pods once other preferred foods have dried up and are no longer available.....it's just a matter of when that will be. Between my low deer numbers and the shear amount of ag in my area and the resulting amount of food I simply don't see much deer use of things like brassica, cowpea, winter pea, sunflowers, sorghum, cereal grains and the like. I plant or have planted those things in the past, but in most cases I end up tilling it under come spring because of it's limited use by the deer. I like trying new things and I like some insurance thru the winter, but it sure can get frustrating. So I now focus on what the deer show me they want and for the most part that is corn and soybeans.