Assuming that the purpose of a "normal" feeder pen is to keep hogs/cows from eating corn and also physically protect the feeder from same animals, then, I think your idea would serve half those purposes. Certainly a lot easier, cheaper and more mobile, so if half the job is enough, then I think its a novel idea.
We don't have many hogs and a cow's mouth is too large for them to effectively pick up corn very well. Could they come by and trample it some? Yes, but I suspect the deer will have eaten most of it by the time they get there.
One of the feeders will likely be inside a 10 acre oat field. The field fence is decent but the occasional cow may venture in, and this will protect the feeder from roving interlopers.