
Several years ago I had a bitch that had a similar split season.
I was worried and had a vet check her out. He used something to look up inside her, and told me that it was just a "normal" season. Although I did disagree with him. And I think I had pyo at the back of my mind.
This was on day 28. We got back home, and I let the gang up the garden. Walked back into the kitchen to put the kettle on, only to find my bitch tied with one of my own boys. She had a litter to that mating.