How many days/weeks before whelping do dogs begin to leak milk?? I am always checking Joy and today I noticed milk coming out of her teats.

I have been searching online but haven't found anything. I have a puppy count x-ray appointment for her on Monday. I really want to know how many puppies she is going to have so that I won't be up waiting for more than she has lol. I also want to make sure they are not too big for her pelvic bone.