Or just use a sheet of plywood for the floor of the coop (on the trailer, above the ground)...and I personally have a little 4x8 trailer from Northern Tool made from aluminum...They have similar aluminum trailers at 5x8 and 5x10. Any could be combined with the hoop coop idea...
But it would take "some effort" to predator proof from the bottom of the trailer to the ground - definitely not an "off the shelf" solution, and would only be appropriate for 4-6 birds, really, unless you planned to move it constantly.
That makes it a safe coop for sleeping, bad weather, predator protection, etc.
Then either let the chickens free-range during the day, or use electric net to make a semi-safe run.
A 5x10 foot coop would be large enough for a dozen chickens (at 4 square feet each).
I see @3KillerBs says almost the same thing, but must have typed faster than me:
Laying hens in a tractor-ish situation are more often given a coop-on-wheels such as was mentioned above as safe night roosting quarters and let out into a run made with easily moved electric poultry netting during the day.