I just wanted to weigh in on this matter. Vanessa, I think it would be wise to read the book that Kim suggested, also "Fiesty Fido", by Patricia McConnell would be a good idea. I also think you may want to consider having a behaviorist come to the house, and give you some suggestions on how to control Chance's reactivity. But, I would suggest ONLY using a behaviorist who uses methods similar the those in the above mentioned books. Chance is behaving as a 'reactive dog'…which means he has turned a normal 'interested' response to other dogs into an over the top, habitual, reaction to other dogs. You can't correct this out of him, because his reaction is not at a rational, thinking level...you have to recondition him, and it will take very specific steps, and a considerable amount of time and effort...but it is definitely possible. I have had lots of clients with dogs who react exactly the same way, and they have successfully changed their dogs' behavior so that the dog is no longer reactive to the activities of other dogs in their lives.
That being said, I don't think that people should HAVE to consult their breeder about training issues. It would be nice, particularly if you are close to the breeder...but not everybody agrees with their breeder's training methods, and not all breeders have any experience with behavioral training. Chance's behavior problems are not based in bad temperament..they are most likely a learned and practiced response to being over stimulated....not really an obedience problem....but something that can be changed with specific training.
As breeders we need to give people MORE than 'teach your dog who is in charge, or get control of your dog.' That means so many different things to different people and isn't very instructive.
Off my soapbox
Oh...and Vanessa....just because you THINK she won't come in until August doesn't mean that is for sure. Chance definitely could be overreacting because she is coming in. The dogs' behavior usually starts to change several weeks before humans can detect estrous is beginning