Thats a great idea, to make connections at the County Fair. That way you can see their best stock too.
Ive never had BCMs so I cant talk about that specific breed, but if they are like practically all other chickens, breed is not all that important. Strain is. If whoever is selecting the breeding stock selects roosters for good behavior and does not allow a bad-behaving rooster to breed, after a few generations you have a flock where most of the roosters behave pretty well. If behavior is not a criteria when selecting breeding stock, who knows what you will get? If you get a bad-behaving rooster once, Id look for a different source for the next one.
Thats why I really dont trust someone breeding chickens for show unless I know them. Some do breed for behavior as well as what the judge sees. These are the ones I consider breeding heritage birds and truly preserving the breed. If all you are breeding for is what the judge sees, a lot of the heritage qualities can be missing.
I find that having mature chickens in the flock will help a young rooster learn better manners. Some hens will squat for anything in spurs, but many mature hens require the cockerel to treat them like a lady before they accept his advances. Sometimes they will slap him around themselves but a favorite tactic is to lead him to the dominant rooster who teaches Junior whos boss and who has privileges.
One of the funniest things Ive seen was a young cockerel was feeling cocky and chased a hen who ran to the dominant rooster. When the cockerel saw the rooster he kept running and swung wide under a shed. The old rooster started strutting his stuff, walking around so proud of himself. That cockerel kept going out the other side of the shed, circled around, nailed the hen, and was gone before the rooster realized what had happened.