need help with gender of 5 chicks

[Rookie Raiser]

i bought 5 chicks from a local feed store in the assorted bantam bin and it looks as though some are getting red combs, but i dont know if it is because they are cockerels or because they are getting bigger. they are 4 weeks old.

here is Lightning (s)he is a cochin:







Nitro, cochin:







Drifter, cochin






Scuffs, cochin







and Daytona, OEGB








thanks in advance!!

 

[roostersandhens]

Lighting looks like a female so far. Nitro looks like a girl so far. Drifter's comb is looking a bit rooster like. Not sure about the other 2..