My normal nests are off the ground which is great for collecting eggs but not so good for the chicks once they hatch so I have tried moving the clucky hen and her eggs to a ground level nest before but with no success. Each time I have done it she abandons the new nest with her eggs in it and goes back to being clucky on the empty nest she originally chose
females 
Your boxes are fairly low so just slip 6 fertile eggs under her and put a couple of your non-fertile ones in another box so the other chooks stop trying to lay more eggs on top of the broody one and let her do her thing. I separate mum and chicks from the rest for the first few months because I have a rooster and they can be a bit violent but with just chooks I reckon mum should be able to protect them while they learn the pecking order.
Sorry no eggs, mine are clucky now too.
