I got 3 chickens on Monday (it is my first time keeping chickens) and have noticed that the youngest (17 weeks) started sneezing yesterday. Today she seems to be sneezing more and coughing. She seems otherwise healthy, nothing around her eyes or vents. They have been vaccinated against Infectious Bronchitus already. She has been quite stressed with the change and got pecked a lot her first few days, but this has settled down now. I believe she has only recently changed food from growers to layers. I don't have another coop to separate her at the moment.. What would be the best course of action?