feeding a broody

one of our black rock hybrids is broody, (4 days now) and we are expecting some eggs from Poulet Anglais today to put under her.  Yesterday we moved her to a broody coop and she settled back onto the pot eggs that she's been sitting on.  When I carried her she felt a bit thin, I could feel her breast bone.  I know that they tend to eat very little while sitting and wondered if I should give her something other than layers pellets for the duration?  We have wheat, chick crumbs and 'poultry finisher' pellets (for fattening hubbards)
last night when I checked she had eaten some pellets so we know she isn't starving herself.  I just want to give her the best care in her confinement! 

thanks foxy, will do that.  I am surprised she is broody, we got her at POL at Easter, still, we are glad too, we love having a mummy and chicks   

My broody was good as gold and got very thin too. She really appreciated the mixed corn and was happy to take it from my hand even as she was sitting. She has got really tame as a result  .

My Black Rock is quite a skinny girl anyway (though a great layer)...