Liz Buchanan BVSc MRCVS
Hello! I am really pleased that you have asked this question but first, please brace yourself for a comment - not aimed at you, as you have clearly discovered how difficult it is to keep entire female and male dogs apart together in the same household. Rather, this is for anyone else reading, because mating is so much easier and faster than people expect - I've heard 'we'll just keep them apart' so many times over the years and I should just save myself time and book in the pregnancy scan the second I hear it. A female dog in season and a male in proximity both become extremely determined. If two dogs tie together in coitus, there is a 50% or more chance of pregnancy. If two young, un-neutered dogs live in the same household, there is a very high chance that they will mate.
It's worth mentioning that chemical castration techniques may now be available from your vet.
Sex ed lecture over, let me see if I can answer your question.