Which breed 'standards' are silly or just for 'looks' and not really helpful for the bird, I wonder?
There are so many dog varieties that are hurtful to the actual dog but humans wanted "something specific"... I wonder what we've done to chickens....
Kirkiri perhaps :/ That cannot possibly be great.
What's wrong with Kirikiri?
I can name a lot of birds smaller than them. Songbirds, hummingbirds, etc etc
They don't have a standard either, at least not here in the US.
It's not healthy to breed from runty birds of course, which I'm sure lots of Kirikiri breeders do, but it's perfectly fine to selectively breed smaller and smaller birds.
I can name Japanese (lethal creeper gene) and Araucana (lethal ear tuft gene). The Japanese standard could be bred for without the creeper gene I feel like. You could just select for shorter legs, but I do feel like short legs somewhat limit movement. I've also heard the argument against Silkie crests. Polish have large crests because of a larger vaulted skull shape with a knob on it but this isn't harmful to the bird (it has a larger brain though but based on studies, it has no neurological effects, nor any adverse effects at all.) However, when this large skull shape is bred onto other smaller crested breeds like the Silkie you can *alledgedly* get an incomplete skull and exposed brain. This is alledgedly, I haven't actually heard of it resulting in problems.
Vision isn't an issue because crests can be pulled back using a rubber band. Or plucked.
You could argue Silkie and Frizzle feathering but it's not just in the Standard, lots of people breed for it.
Silkie feathering isn't inherently bad for the bird and in my experience Silkies are extremely hardy despite what they say. But they definitely can't fly so I'd argue that would make them less happy. But then, a lot of birds can't fly. Have you ever seen a sad Ostrich?
Frizzle feathering is more of an issue. Homozygous frizzle birds have terrible, brittle feathers that don't provide the protection the birds need. Obviously just don't breed frizzle to frizzle but I personally don't see the point of perpetuating a gene that does that. But they are cute though.