It is really hard to tell them apart when there are only a few spots. Not what you want to hear, but it could be either. Pox usually has a more of a white lump look, peck marks look more like black scabs (which they are) I suppose you can pick one off and see if it dissolves in water to blood. Time will tell- pox will spread, then go away in a few weeks. Peck marks will usually stay with the low birds in the pecking order, or the rooster's favorite hen.... a peck mark will also heal faster than a pox mark.