selective breeding for show?

[Mykee]

I am interested in breeding for show. I don't want a really big flock, no more than 20 for sure. I tend to become attached to my birds, so culling is very difficult for me. I think I'll start with a few hens and a rooster, but when I breed/incubate, if I get a better rooster, should I keep the better rooster, or keep breeding the original? Do you have any suggestions for what to do with birds I don't want to keep? (I am specifically interested in blues.)

 

[Narragansett]

I suggest that you attend a few APA/ABA sanctioned shows and talk to some of the exhibitors there. Your restrictions make it very unlikely that you will be succesful in the long term with a show line.
Culling is a fact of life when breeding to improve any trait. Without producing large numbers and choosing only the very few to breed with for improvement, you won't get anywhere. You can't keep them all. A poultry flock is not a static exhibition unit like a horse or even a dog can be. The exhibition life of a single bird depending on species, breed and variety may be as little as one season, but seldom more than two or three. It's fine to develop an emotional attachment to your birds, but if you're going to be a successful exhibitor breeder, you'll need to have a different, more practical, sensible, mature outlook.
Blue is not a breed, it is a variety, found in several breeds. The way in which that color gene behaves in poultry leaves a much higher number of culls and nonshowable birds than in other varieties, reducing your potential exhibition birds even further.
It's not impossible to be a successful exhibition breeder with a flock of only 20 birds, but you'll need to focus on a simple color variety like white, and hatch dozens if not hundreds of birds from which to choose from each season. There are only so many pet homes or people interested in wasting a lot of time and money growing Standard-bred culls for the table, even if given them for free. You'll need to start out with the best quality that you can find, and that means buying started breeding stock from a top breeder. You won't establish a successful exhibition line with a flock of only 20 by starting with swap meet birds, eggs or chicks.