In most cases, choice of crest shape is by quality, yes. Not always but most cases.
As for fixing vs culling, depends on how bad the fault is, how genetic it is, and what you have available.
So, if I have a squirrel tailed male, and some well angled tails in my females, and I've no other male or no other source for a better male, I best just work on fixing it with the females.
But if I have a choice, and there's a better male around, I best use that better male. And if the problem is worse than say a squirrel tail, I best cull him, yes.
I guess a better example is with females - If I have a flock of pretty decent hens but one just doesn't par up with the others, and especially has a trait I'd prefer not to see, why should I keep her if I have other better ones? As someone said not too long ago in another thread, it is better to work with a small number of great birds than a large number of birds who are "okay."
Now of course, in my case, I don't have a single Polish here who really is great, everyone here has a trait that surpasses the other but a flaw that drops them below the next, and I've only got so much of each color/line, so, I'm keeping them all right now until I get what I want out of them, otherwise, I could lose them tomorrow and I'm really not in the best position to add new blood or replace some right now.
After getting a really nice scale I've found that I only have one bird who's above the SOP weight, and only 2 others who are perfectly there or nearly meet it. The rest are badly underweight but not to the DQ point. And as mentioned about good vs bad, my heaviest male has a terrible comb issue that I just don't want to continue seeing anymore, so, it's a big struggle. Plus none of my current males have tails below 80 degrees above horizontal, and my hens with such are the lightest in weight.
So, of course, as said, it narrows me down to a slim picking of who to breed for good stuff but in the mean time, not getting rid of anyone yet, as I can't afford to lose the remaining better birds.
Anyway back on the cull vs fix issue, I think of it this way - If I had a bird with a fault, and I "fixed" him with a better female, the offspring will still carry that fault whether it shows or not, and eventually down the road it will pop up again. Best I get rid of it all together unless I really need that bird, and am aware of the fault in the future, and carefully breed it out the next generation. That or replace later when I have more, better stock.
I'm fully aware that my smooth Tolbunt has a bad comb. And so far it really does influence the offspring cockerels. Ugh.
