Were her spots last week like any of the pictures in the links? Pox can start out with a yellowish bump turning into a brown scab, and some will look bloody at first then scab over. The Partners/Cornell link has pictures of different types of pox. If this is pox, and I hope it's that and not a tumor or abscess, those are some big bumps. If you have more pictures to post tomorrow, more people can see this thread, and keep it going until you get some answers.
So far all the bumps appear to be the same. I will take more picture's tomorrow and post them. She is eating, drinking, and acts like any other hen; they don't seem to bother her when I have looked at or examined her.
I lost one pullet last year for an unknown reason. None of my other chickens are sick, nor do they have any spots, and no none of my hens have had any vaccines. There hasn't been any signs of lameness with the sick bird either. She eats, and drinks normally, even free ranges with the other hens when I let them out.