Feeder pen to keep cows out

[BigL]

Your not going to grt it tight ( and stay tight ) with out running bracing wires to strong stakes in 2 directions off each corner. You would be much better staking down hog panels. That is unless your using trees as part of your wire fence.

I did a 32' diameter pen and wires stayed tight until tress fell across it. So far have removed 3 pecan trees off the fence that have bent poles and had to only retighten the wires. Pretty easy if you have a wire stretcher.

[Big pig]

Barb wire is fine but the deer will not react negatively to hog panels if you decide t0 go easier option.

This. I actually had a doe in my pen the day we built a hog panel pen!
Hand corn is your friend too. FYI. Round pens are easy.

My not-so-tight barbed wire keeps cows out.
I used minimum posts and twisted "stays" to keep wire separated at the right level for cows.