Depends on the dog…. I have usually spayed (if I am going to spay) before the first season. If you wait till they are a year, they will have had a first season.... As long as the bitch is heathly, spaying a 6 to 8 months is fine, IMO... some people like to wait till they are done growing, however then you have to put up with 30 days of them being in season... neighborhood dogs, male dogs in your own home after the bitch (neutered or not as a neutered dog can "tie" a bitch, just not produce puppies).. bitches after the boy to breed her... yes they are sluts...
Bitches can get really "rotten" when they are in season.. clingy, moody, no different then us humans. And they can and many time do think they are with puppies... get milk, get fat....get really moody and what I always referred to as the "funk" for two months after they have been in season (two months would be when they would have had puppies if they were bred)... and yes, they can get preggers at that age.
And once they are spayed they will never come in season
And yes, Vanessa... Chance will change... and so will she... in the beginning of her season when he comes sniffing around she will roar more then usual at him... when she would be ready to be bred, she will "hound" him... the minutes she is past breeding time, back to roaring at him.... oh and you might find times that she humps him.....
Have fun!!!!