Female Boxer in Heat????

Question
I have 2 Boxers, a male and a female, the male is CKC registered and the female is AKC registered.  They are both 2 years old.  How often is the female in season and for how long? How often is she in season?
My male has shown her no interest until just recently now it seems he won't leave her alone, is this normal?

Answer
Female dogs can come into heat as often as every 4 months to as little as once every couple of years.  when they are in heat it lasts about  3-4 weeks.  They are usually fertile the 13th day, but this can vary to as early as the fourth day to as late as the 24th day
nancy