I planted them for 2 years about 3-4 years ago. Planted about 2 acres in two plots and while they didn't get real big they didn't eat them to the ground real fast either. Not sure they were worth the extra cost of the seed and shipping was killer. I feel there is better bang for the buck out there.
I planted Eagle forage soybeans last year in a 1/4 acre spot that I wanted an annual before switching to clover. Agree with other posters. Deer need to be kept out of there in beginning stages of growth. They did eat them, but since such a small plot, they never had a chance to grow very big. One other thing: Have a plan to plant something in that area when soybeans are done and eaten. Mine were finished in august. That left area barren all through hunting season. I should have followed them with brassicas, but didn't have the time. Here are a couple of pictures from last year. Overall, not worth it to me. You may be ok with one acre if deer density is not to high. Good luck!