We have a 4 year old male gsd and an 8 month old female gsd. This morning the male mounted the female for the first time I’ve seen. She is swollen but how do i know if she’s fertile? We are trying to keep them separated now (since this morning) but generally they spend all day outside together in our backyard and inside in the evenings when we are home. So I don’t know if they’ve mated before or not. Any help would be appreciated!