Destiny is off on the numbers for pens, for market and egg layers you only need a pair per pen, the breeders are a trio. Maybe confused with rabbits

which are a pen of 3. But the rest of her info is spot on. I think part of the reason for the after January 1st hatch is to keep a level playing field. The birds hatched within the year they show will never be fully mature for 4-H shows, but the earlier they are hatched the better so they can have ample maturity and feathering by show time.
I do need to correct Cluckies, I do show and breed but I am NOT a judge. I aspire to be one, so have studied up a lot on poultry, but not there yet.
What I recommend to folks just starting out or coming late to the game for starting their chickens, try layers. They will be in the laying stage earlier than the breeding groups and have a little less to worry about in the beginning. Get a feel and understanding of what to look for in a good production bird and get your feet wet. This will give you time to research what you may want to get into for breeding birds in the meantime. Where breeding types should be hatched in January, February at the latest, you can get chicks now (early March) for the layers and still get decent develpment for show. I wouldn't wait though. For the White Egg class, I wouldn't bother with anything besides Pearl White Leghorns. They are the ones that compete and win every time. For the Brown Egg class, go with the Production hybrids like Red Production, Red Sex Links, Black Sex Links, ISA Browns, etc. I would suggest for every pair you want to have, get 10 and pick the two that look the best that match. You can always find people to buy up your extras. I would consider raising the Cornish Rocks for the meat class too if you are interested in growing your own. They only take 8 weeks to grow from hatch to ready to butcher. They are mess though and you want to keep them clean throughout their time with you so they show better.
Like Destiny said, each club is different, find one that matches your expectations or what you want to focus on. Network with other people interested in poultry, ask the county office who they know who are their poultry people and who the poultry supervisor is.
There is a lot to learn when you start out, but it can be so much fun and so rewarding when you show they and when you get meat and eggs from them too.
I do not have anything to offer this year. I haven't even turned on my incubators because I have had a lot of family stuff going on and am taking a break with my birds this year, sort of.
Good luck. If you can't find a breeder,
Tractor Supply and Runnings and some elevators should be selling the egg laying birds I mentioned and you could get started there.