> how slowly do the other chickens grow?

Here in Norway the two largest producers are moving[1][2] from Ross 308 to Rustic Gold[3]. They live roughly 40-50% longer. The third largest has already moved[4] to the hybrid Hubbard JA 878, with similar growth.

However it's also easier to get the slow-growing chickens larger without health issues, roughly 25% according to this[5], so it turns out you might need fewer chickens to produce the same amount of meat. And thus the economics might not be as bad as it looks at first glance.

That's for Norway though, perhaps it's different elsewhere.

[1]: https://www.nortura.no/b%C3%A6rekraft-i-nortura/omsorg-for-m...

[2]: https://kommunikasjon.ntb.no/pressemelding/18709900/coop-tra...

[3]: https://aviagen.com/eu/brands/rowan-range/products/rustic-go...

[4]: https://dyrevern.no/landbruksdyr/kraftig-velferdsloft-for-no...

[5]: https://www.norsklandbruk.no/den-vanskelige-okonomien-i-a-by...

> Most lay opinions I can find online claim the fast growing birds to have inferior meat quality. I wonder if I could distinguish in a blind taste test.

It’s easy to distinguish.

The fast growing birds are much larger, breasts at least 2x the size of normal chickens.

The larger breasts you notice when cutting them when raw, they often have a tough texture and meat inside like strands. When cooked and chewing it’ll have a hard chewy texture, sometimes feeling raw/uncooked. This is called woody breast.

If you have a standard small chicken breast, the texture feels much more pleasant when eating, like chicken.

I always try to avoid large chicken breasts and get the smallest possible but it’s virtually impossible now unless you live near high end low volume butcher with their own independent supplier.

> I wonder if I could distinguish in a blind taste test

I find it genuinely baffling that that would be the point.