My chicken is not divided half and half, but is a purebred splash silkie, nice quality,.... at almost a year was sold as a hen (to me). After having it awhile it starts to crow. No biggie, silkies are notoriously hard to sex- except still no cockerel comb, no streamers. It starts developing streamers, still no change in comb, continues to crow, quite a lot and loudly,.....
Then, a week or so ago it laid a very tiny, big marble sized, egg. It could not have been another bird, I had it in a separate cage while deciding if I would use it to breed, so the egg was definitely from the splash 'roo'.
No eggs since, and the bird still crows frequently. Put it in with my sole laying hen (a little silkie-cross freak that was supposed to be all silkie) and the splash bird mounts her. Holy moly. So, by now I have no idea if the bird is a hen, a roo, or a hen-roo (hermaphrodite).