Dopey is very quiet at the moment. Yesterday she was standing looking very uninterested in everything. Today she came out with the other chickens, and had a huge drink of water, before going in to the nest box, presumably to lay. She has been there a while - I went to check on her and she seems ok, so hopefully she is just trying to lay a big egg. I hope there is nothing more serious wrong with her. One thought was that she may be egg bound - I think the cure for this is to stand the chicken in a tub of warm water which helps them to lay. I will try this if she doesn't improve.
I think I will also give them a 'protein boost' this evening with some cat food, hard boiled eggs and poultry spice. But I hope Dopey will have picked up by then.