I had to come up with another solution.
The greenhouse, some cardboard boxes and lots of straw. Just for a few days, with access to outside for a bit of pecking and scratching.
In a few weeks they'll look great and become happy birds (that lay me lots of eggs). In the mean time they need a bit of care to bring them up to health.
And as for the three I've got left from last years batch (after dog and fox attacks), I was going to kill them to make way for the new ones but they're still laying really well, have no idea that they're meant to stay in their pen and love wandering about the whole smallholding. I think they can stay.