The youth class is through 18 years of age until the youth's 19th birthday. A youth may enter either the youth or open show (but not both in the same show).
6 classa class for rabbits with an ideal weight of over 9lbs. 6 class rabbits winning their breed compete for best 6class. Smaller breeds compete for best 4 class and the Best In Show winner is chosen from the 2. Some shows choose the final winners differently by doing best of group rather than best 4 or6 class.
Six class is referred to as such because it has the additional buck/doe intermediate 6-8 month class that the smaller breeds don't have (they just do buck/doe senior and junior classes).
ARBA has national youth competitions based on different age groups where youth can compete in royalty, judging, breed id, management and achievement contest.
(Not sure if you were referring to the actual rabbit showing or ARBA youth contests based on knowledge.)
I was just wondering because I was looking up the person I am getting my rabbit from on the internet and alot of rabbit show sites came up where she had placed. I didn't know what those things meant,but now I do . I guess the girl I'm geting my bun from is under 18, which isn't a problem but I just wanted to check.Plus she must have good rabbits because she won best in show a few times.