The only major sign of a breeding you might notice is a very distinct smell from your bitch's rear quarter that is more noticeable than any odor related to her heat cycle. (dogs.lovetoknow.com)
Additionally, gather some ingredients with distinct smells to put in your new smelling station. (playconnectgrow.org)
It isn't even like they have their own distinct smell. (therusticpig.com)