I'm looking for an inexpensive way to divide my backyard.

Old Pallets

I don't know how you are going to keep the KIDS from jumping but you can always put a runner (like a clothes line) up for the dogs. Just attach a leash to the runners so they can't reach the areas you want to keep them out of and also so they can't get tangled up in each others leashes. We did this with two dogs and 375 foot runner with a 50 foot leash for each. Worked great.

Good luck keeping the Great Pyrenees from being with the kids. I had one when my kids were little and she lived to play with the kids. She was 150 pounds at six months. She ate a redwood planter, a bunch of our deck and a really old grapevine. We found a farm that wanted her and would let her eat wood to her hearts content and run the fences that she was bread for after we had to replace rails for the fourth time in one summer. The pallet suggestion would let you put up fencing for little cost. Wire fencing would not stand up to your big one.

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Free pallets everywhere... https://www.hometalk.com/diy/outdoor/i-love-pallets-31503216?r=1

https://www.hometalk.com/diy/outdoor/i-love-pallets-31503216?r=1