I have new 4-week-old pullets arriving tomorrow or the next day from McMurray. Should I isolate them from my hens, to make sure they have no disease, or is it safe to go ahead and put them in the pen right next to my coop/run? If you think I should isolate them, how long should I do so? I would think, coming from a certified hatchery, that they would be fine, but I do want to be safe. What would/do you do?