Hatched chick sexing ?

[Chickentender321]

I hatched 2 chicks by accident a week apart. Any way to guess their sex this young for fun? It doesn’t really matter, we just are curious! First 3 pics are the almost 2 week old and the last pic with the white head is almost 1 week old in 2 days. We just adopted the moms so breed is unknown. They hatched out of green/blue eggs

 

[Fwoof]

I've actually had success with tail feather sexing for my first hatching!
Female tail feathers fray out and are fluffier (think of a dandelion seed), whereas male tail feathers are wispy and slanted, either down or to the side. Definetly not foolproof or accurate, but worked for me before!
Also I've heard that females feather faster than males, depending on the breed of course.