Broody cage advice

Hi. My broody is still broody, now in her 5th week. I've not had this problem before, they've always been OK after their 3 weeks is up, but this one's showing no signs of changing. I've been periodically putting her into a solitary space with a plain concrete floor, just with food and water, but it's not working. When I let her out again she goes and perches on top of the coop where they all roost at night, not in a 'nest' any more. She's been eating and drinking enough that I'm not worried about her, but my patience is now at an end. I've not got a broody coop - managed to avoid having to use one so far - but am wondering if this dog crate would do, placed under the trees in the garden? I'm not really sure about the bird's feet in a broody coop - I would have assumed chicken wire or any other wire might damage them? The bars on this are much wider than chicken wire of course - is it therefore unsuitable?

Ta