I just ordered 15 chicks from purely poultry and they should be here in the next couple of days. I spoke to a girl on the phone about getting the Mareks vaccine for them and she said since there have never been chickens on my property I don't need to get it. Well, I didn't think about it then but I'm borrowing a friends chick brooder to start them in and it clearly has had many chicks in there before. Are my chicks going to be okay in there or am I in trouble? Thanks in advance!