Hi Nissa;
I don't see why that would not work. At least for a while.
I am not sure how long it would remain movable with the original wheels.
If the original wheels failed you could build a slidable bottom and pull it where you want it to be.
The only downside I can think of, is old trailers are not very good-looking...
I would not want to bring them on my property and then 5-10 years later have to deal with disposing of the now (really ugly) old wrecked trailers...
Oh, and I would imagine the goats will thoroughly stink the place up after they test chew everything...
It's a good repurpose if you already have one.
I would not want to bring in any extra I have
enough to do already.