You can save a lot of money by just using 2 or three strands of barbed wire. I have just 2 strands around my feeders and the cows can't get in. I have a cow on the game cam, just looked and walked off. Cows are easy it's sheep that are a beeoch.
This right here ^^^^
I use barb wire and T-posts because all we have is cattle on our lease and I have not had any cows in the feeder pens. Got pics of them looking but none of them attemting to get in.
I had barbed wire around my feeder, as all I had to worry about was cows. made the circle really wide, so no corn got outside the wire and never had any issues with cows getting into my feed pen. Of course you will need wire stretchers to amek sure you get it tight enough, otherwise the cows will just go right through the fence.
Then opening day of deer season this year, we got hogs. The barbed wire didn't faze the hogs one bit and they didn't ruin the season, but I think they kept deer from being as willing to go to the feeder although the hogs were only nocturnal all season (finally got one in the daylight hours a couple weeks ago). Anyway, got some field fence from TSC and used that around my pen...now I have pics of many deer in the pen nearly every night and no hogs at all.
I am in the process of building a second feed pen on a different part of the lease. I used the rest of the field fence and will finish it with hog panels. The second one is smaller than the first, so I will use probably 5 panels to finish the half that is not fenced right now. To use panels for my initial pen it would have taken easily 16 panels, and that was just too much money when the field fence was half that price.