I read that you can do a side project for a trait like feather quality. Pick the birds with the best feathers and breed them; when they mature, pick the best of those to mate; continue. The difference is you only look at the one aspect of the birds when you're making the breeding choices (within reason?)... and eventually you breed something from the "feather quality" line into the "whole bird" line.
Obviously I haven't tried that yet ... I've bred exactly zero birds that I've had to pick out myself. But I think PapaDel's feathers are nice enough he helped with the F5s. They are fluffy but not loosely feathered. I did read some descriptions about how to run your hands over the bird to assess feather quality. I gather you can also tell some by watching them when they're out in the wind (feathers shouldn't lift too easily, even in fluffier breeds).
Then the rest of what I've learned about birds with nice feathers is about feeding the birds good nutrition, making sure they have good dust bath areas so they can take care of themselves, and also managing pests. You can include extra cockerels in the list of pests, IMO.
