Both of my boxers had kennel cough. They hacked up a white mucas about every 1/2 hr for 2 to 3 days.
If your boxer is hacking but not producing anything, then I'm not sure it would be kennel cough. Possibly but I would keep an eye on her. If it does not resolve itself in a few days, you might want to take her in to the vet.
My own dog has had it 3 times, only 1 of the 3 did he ever hack up anything. And I've had 1 foster with it and 2 pet sitting dog with it, none of them ever actually hacked up anything. In my 6 experiences with KC it's always been a non productive hacking/honking for weeks (ours has lasted 3-4 weeks with all of our bouts here), minus the one time that he was hacking up white foam for 3 weeks.
Well we also have a dachshund if it was Kennel Cough wouldnt it pass on to my Dachshund Maddie?
Hmmm.
By the way my Roxy just got mischievous and I found half ate bar of dial soap on the bathroom floor. Haha.
Hmmmm.
Well I also have a question about her turning 7 months today when should the cycle start and how do you know its already in effect?