APA and the particular show rules can sometimes differ slightly for hen/pullet etc. Cocke County show says 1 year old and they are a hen or rooster. This is the most accepted definition.
Prepare....Stang, barnqueen, daph, or tncknut can better answer that.
Cages are there and you can coop up (at least at Cocke County) the night before if you want. If not, you want to be there by about 6am
You can technically show any age above chick (I think)....but I would advise against anything younger than 5 months. They have not "fully" developed color, feathering, and weight enough to hardly qualify as Pullet. (Stacy...can you correct me on this please if im off a bit?)
I'll be at newport pretty early and I think Megan is going to show a Welsummer pullet, so if you want me to meet you there and walk you through getting registered, tested, and caged up...it's not a problem. I'll get the # for you to call and get pre-registered as we get about a week out from the show. Remind me.....
Yup, I touched on that with points and how if they are too young, they will lose points.
As for prepping them.... that is what really makes or breaks you often. Bathes, nails trimed, combs feet and wattles oiled.... but never get caught plucking a feather! You'll be disqualified on the spot.