I've been debating the cattle panel shelter for a long time. I'm wondering how durable they really area, and what is the cheapest/best cover to use?
We need one for a different reason - to put a roll bale under so the goats can have it freechoice vs. having to fill hay feeders 2/3 times a day.
As for smaller pallet shelters, they can be easy to make, just depends on how much you want to do with them, how long you plan to use them, etc.
For temporary use, you can nail them together, and run boards across the top, then lay OSB and cover securely with a decent tarp - we've done this with success, although it can be unattractive lol Of course there is the risk of the goats tearing up the tarp. We had 3 young wethers tear up a tarp this summer on one.
For more permanent I'd find something you can set it on. We built our barn with pallets, and buried wood in the ground - seasoned tree trunks that aren't too wide, and buried them in the ground, hubby made sure everything was level. I can show pics if anyone is interested in how we did it.
Nail the pallets together, nail OSB on the top, and around the sides. You can paint the OSB to protect it, and can get some kind of roofing. Metal is cheap, but the ends can be dangerous/sharp, so if it's a low laying shelter, you'll have to bend the ends so they can't hurt anyone.
Lowe's sells something in the roofing supplies called Ondura <spelling>, we used this on our barn, it's really good stuff, easy to install, safer than metal, but it's more expensive. I think a 4x6 sheet is about $18. BUT...smaller shelters wouldn't take much.
Just some thoughts.