Good idea. I’ll have to do this check tomorrow, as they’ve gone to roost. Ruby is on hormones and should NOT have an egg in the works. However, I’m well aware there is a good chance the hormones won’t work at some point. And then it might be time to put her down. Ruby is four, so I was hoping her laying would slow way down on its own.I haven't read ahead but...
Can you look at her vent when she's doing this?
It looks to me as if she is trying to lay an egg. Sometimes, even if there is no proper egg on its way hens will do this. Something in their reproductive tract signals that an egg has been made and needs pushing down the tract.
If there is an egg, even if it hasn't been shelled yet, her vent will be moving as the muscles that move the egg downwards towards the vent expand and contract.