I have a flock that is currently being treated for respiratory illness that were once free range but are now in a very large fence. I took a few to the vet yesterday and have tylan powder on order for the whole flock that will be in either Sat or Monday. I also have new baby chicks that are being kept in a separate pen what do I need to do to make sure that the babies do not get sick. I am most concerned about them coming into contact with ground that the older flock was once on.