Built two new pens due to cows tearing up feeders. I built them with 17 T Posts set 10 feet apart in a circle with two strands or barbed wire at knee and waist height. Pens went up iri February and the deer have stopped hitting the feeders. Did I build the pens too small?

What is the diameter? Might just be time of year.....lots to eat out there right now....

160ish foot circumference

So about 50' across....25' from the sides to the feeder if its in the middle....seems a little small to me...only 8 yrs to the feeder seems tight...

If the circumference is 160' then the diameter is about 50'. If the feeder is in the middle this would give you 25' from feeder to pen.

Roughly 25 feet from feeder to sides of the pen.

That plenty big. Thats the same as 10 hog panels. Our best feeder is only 7 panels. Gets more traffic than ours with 11. We have one with 2 strands of barb wire and they usually go under it.

I build mine with 10 hog panels, so about the same size and I have no problem with deer getting in it. However, it is very slow right now with everything greening up. I think you will be satisfied with your pen size once they start hitting it in the fall.

I like 14-16 panel sized. but mainly because there's enough room for corn protein and cottonseed.

50 diameter foot shouldn't scare them off.

We build ours 60' x 60' so 3,600 square feet. Deer use them just fine and even bed down inside them from time-to-time. We also leave some of the trees and brush in ours.

I think you're not seeing deer in them due to normal spring green up.

Cows that associate feeders with a food source or a good place to scratch are a little harder to exclude than ones that never show an interest.
2 strands of barb wire wouldn't keep any cows or calves I've ever owned in or out of anything they were curious about.
Bulls just lean/push in on a T post until bent & wire slacked then walk right in.

I've only had two cows get into a feed pen made from 34" hog panels, one got a ride to town the other went to a pasture with no hunting.

I've seen deer regularly jump into pens half that size. They're plenty big.
Give the deer some more time, they'll find them and start visiting regularly.

As others have said, two strands isn't enough. The first one I built was about the same size. We mostly had yearling steers on our place. Then the LO brought in some older, momma cows. The 3-strand one I had didn't slow them down a bit. So, up went two more strands and the fence-stretcher was used extensively. That seemed to stop them from tearing things up. Now the hogs, on the other hand, I don't think they even knew there was a fence there.

Plenty big enough. I'm not getting a lot of activity lately either, hardly any protein use, they'll be back. I use hog panels with 2 strings of wire around the top. I try not to fill when the cows are near, just as a precaution.

I have 16 sixteen ft. hog panels in a circle with two strands of barb wire on the top for my pen. Works just fine. Room enough to drive a pickup in, turn around and drive back when filling feeders.

I just acquired a new lease and I plan on using 15-17 16' hog panels for my feed pen in a squarish shape with round "corners". I'm using an extra t post between each end of the panel. I found that if you have loose panels, the cattle feel better about pushing on it and coming on in. If you use the extra post in between, it secures each panel better and so far, fingers crossed, have had better luck this way on cattle coming on in. I have had the push through in the past but it was on a loose pen I want it big enough to put up 2 bulk feeders (one protein, one corn) with plenty of room to move around. I'd prefer them to not even know they're in a "pen". The thought has crossed my mind to do 30+ panels and plant stuff in there as well, but I haven't done that yet.

That will work, mine is as round as I could get it. Forgot to tell about the post in the middle but ours has it,

Also just depends on size of property. Old place 200 acres had a bull jump in non stop. Finally took them down and no issue. Place now 1,100 acre not a single cow comes close in 10 years. They just walk by and deer come out right after. Have 6 pens.