Cattle Yard Panels

We have German Shepherds TW. The male is 135 pounds ... not aggressive, just big. We live in the city today and have a pen of cattle panel made for them in the backyard. We head to the country and make a new pen for them. The cattle panels are working well, but there is no option for a door. We need to find something which is hard because he loves to jump on the pen when we walk up. We would prefer something short .... we do not want much more than 4 '. We did go out on a daily basis and who really loves a door (which is the only thing we did not like the signs of cattle). Ideas??? I found things online, but everthing I am finding is very small and as a kennel. Our dogs are outside dogs (they are too big and with a famly of five we have simply no room for them inside) and, although they do go out every day, I refuse to put them in a pen where they cannot run. Please share your ideas with me.

I tried to understand that myself. I thought of an overloading of rope between two trees so far away. And let loosly leaning against the rope so that the dog can run back. When I am outside, it is not on a leash or a rope or a pen. She manages to run around our 3 acres free as a bird, and always comes when I call. I also walk him on leash to show him the things she can do and not do. But I also leave the inside of me. I could not bear to see her tied up or penned. Especially here where there is so much space to run. If I leave the house without it I put in a kennel where she sleeps about right. (As a niche within, but a bit smaller).

a pen for two German shepherds? a giant backyard, not a pen.

Kennels Prefiert I said that wrong, but they are welded and a kennel, you can buy several signs 10/10 enlarge. It is available in 4 'or 6' tall. And a door. I've used for years and they last for years.

Oh that's easy! I used the "cattle panels" make me huge pens for my yard, not to leave.
I use the panel itself first. Three sides as long as you want 20 feet or 40 feet as you want. The front panel can be cut for a door. I cut an opening large enough to enter and exit, leaving about 1 m solid foundation. If you cut carefully, you can use the cut piece to a door by bending in a half-loop at the top of each side to replace door. Leave long pieces slip into the bottom of the panel itself and pull toward you and hop a door. If you like a mailbox you have a picture so you can do yourself. We each have 10 points and a door like that. If a dog leaves big bucket we put snaps on each side to keep them in. This allows us a door for daily use and still our big beauties in when they are out playing for a while.
BTW I love the 2x4-inch panels best cattle that they can not step or put their head through anywhere and they are really strong. Yes they cost a little more, but then so what. The dogs are safe at any time you decide to let them play outside.