Give them a few days, the pecking order takes a little bit to figure out. If your hens are laying and the new one is not that age yet it could go on until the new one lays. Next time you buy more I suggest that you keep them separate for 2-4 weeks so that you do not infect your entire flock if the new ones have any problems. Because you did introduce without separation, I suggest you do preventive measures for the most common problems. Poultry dust or Sevin for lice, oil on legs for leg mites, and either a wormer or garlic in their feed for worms. This is just in case the new girls had any problems. There are much worse problems that they could bring to your flock that no preventive measure except isolation from your flock will prevent. Watch all your girls closely for the next month because if anything new came in it would most likely present in this time.