There are two kinds of feather sexing. Well three if you are talking about the hackle and saddle feathers the boys get after 3 or 4 months of age.
Sex-linked feather sexing is a scientific method based on the genetics of the parents being set up a certain way. The father has only the recessive fast-feathering genetics. Th mother only has the dominant slow-feathering genetics. For a few days after hatch you can look at the wing feathers and determine if the chick is male or female. You can only do that for a few days and these chicks are not set up genetically for it to work.
The other is based on mystical mythical magic. Nothing scientific about it. Using this method you are usually correct 50% of the time. A coin flip is as accurate.
I'm only guessing, but think I might have one roo and one hen, but unsure because one chick has long feathers and the other doesn't. They are 4 days old chicks