I think it's more common in some breeds than others. I once had a Maran hen
that grew sickle feathers/saddle hackles for one season and used to attempt
to crow. She was an exceptional layer, and the long feathers did not
grow back after the next moult. Oddly, she had the very close barring that
Maran cockerels have and was unlike the others maran hens, so maybe there
was something odd going on as I've never seen another Maran like her (though
I wouldn't profess to be an expert on the breed).

--- In smallholding@..., "auntie_mabel" <karence@...> wrote:
>
> Thanks Elizabeth, all the books and poultry mags I've read and I've never come
across it once!!! I wondered if they might be transgender chickens!!!