A bitch won't wait for another to come in season
A bitch in season can bring another into season if she was due.
I have never had a bitch with 6 monthly seasons, mine go 7 - 12 months. My solids have seasons more regulary than the pati colours.
The time between the first and second season is usually ( in my personal experience ) a good indicator of how long they will go between future seasons. I have not had any bitches " skip " a season but know of bitches that have irregular seasons and some that have silent seasons
i.e no colour and very little swelling.
Tracey