Yup, this started happening with a couple of my hens after the cockerel died, espescially when I put them away at night - instead of being herded into the coop they stop and squat in front of me so I have to pick them up and physically put them away!
I've had this problem with a number of silver grey dorkings, I think the issue is a humidity problem but sometimes it just seems to happen. However it is curable and when the leg muscles build up the adult bird will be fine.
Firstly try a less slippery surface, hessian or a sticky rubber...