I've found that when seeding it's good to put another frame over top until plant roots are well established,
or they pull the entire plant out of the ground instead of nipping off the tops.
They do take some maintenance ....
....I raise them up (for maybe 20 minutes-no more) once in awhile the let them 'clean' them out, with a little help from me and my rake.
Welcome to BYC!
Do you mean raised beds for growing vegetable?
You'd need to cover them so the chooks wouldn't tear them up.
Maybe you mean grazing frames, to provide them with some greenery to eat but not scratch into oblivion?
This oughta get you started...