I know it's really early but I'm wondering if I have a major clue here

[KDbeads]

These 3 are all from the same hen/roo who to the best of our knowledge are MUTTS. Roo was kinda feather legged, hen is clean legged. DOB is 9/23 for all three. Will the females feather out faster even at this young of an age? Because on of them is growing way faster than the rest!!!

Miagi (boy?)

Danielson (Girl?)

Karate (boy?)

 

[RAREROO]

With yours supposedly being mutts, I'm not sure if it will work, but some breeds can be sexed by that method, for example I ordered sexed BOs and SLWs from a hatchery and the females feathered out faster in the wings and tails than the males, however it does not work with some breeds , ex. I thought that I could sex my speckled Sussex like that because some feathered out faster than the others, I only saved the rapid feathered ones and some turned out to be males. Same way with my BC Marans, out of six, only two were rapid feathered so I thought those two were hens, It turns out that they are actually the best pair in the bunch, one hen and one roo, the other 4 are all short feathered and judgeing by the combs, 3 are roos and 1 may be a hen.
So to answer your question, that's not always an acurrate method of sexing,espcially when you don't know the breed.