It is important to know the due date and be certain of it. It is easy to mark it on the calendar and then have them cycle again and get rebred 3 weeks later. Then if you lute the doe on the first due date you will have premies that won't likely live - so be sure of your dates. I put a marking harness on a buck to get some fall kiddings. I have a doe who was marked by the buck and due last Tuesday. However, i would not lute her because I didn't witness the breeding. She is making an udder but still has not fully developed it - this is her first kidding. If I had given her lute - she would have kidded prematurely. However, if you are absolutely sure of the date, I would not let them go over. If they don't kid on the date - then I would consider giving the lute to bring it on. Otherwise the kids get too large or even die in the womb.