Don’t do it! Do not feather sex before 4 weeks of age, most or all will be girls and then a week later they are all male and your dreams of raising quail will be shattered until that other batch of eggs you ordered (just in case) hatches and then you’ll have them coming out your eyeballs. Those darn baby spots! Italian/fawn males often get chestnut colored feathers on their head which can be helpful early on (except homozygous fee which come in black like a hen), but my first hatch of 5 birds was all female at 3.5 weeks and at 4 weeks I only had one girl. This last hatch I had 3/12 feather sexable plus 3 roux birds (sex linked recessive) out of non roux hens (must be female). Had no idea on the rest, so went out of town for a week and they are all crowing when I get back, easiest bird sexing I’ve ever done but it certainly freaked out my bird sitter (she has only female chickens). I really want to make a ring tone of five adolescent males crowing at once! It is hard to wait but you’ll know in a couple weeks.