I have three Pekin hens that are exactly 6 months old,I assumed they were all hens however recently the lighter one seems too look like a boy however it doesn’t make a sound, so what see what your opinions are ,boy or girl?
Yes, he is male. The lightness you see is actually an indicator that he is male. He is double-barred, and whilst males can be single- or double-barred according to how many copies of the gene they have, females can only be single-barred (dark-barred) as they have only one locus or 'slot' for the barring gene.
It looks like you have one boy and two girls. Some pullets can get decent sized combs and wattles but at 6 months that is pretty impressive. The bright red comb and wattles is another strong hint, but if a pullet is laying her comb and wattles are usually pretty bright red too.
What really gives it away is color. Those are all barred/cuckoo. Barring is a sex linked gene. Females have one copy of that gene , males have two. When both those genes at that gene pair are barred the males are much lighter than the females who only have one barring gene. Don't expect any eggs out of that light-colored one. He won't lay any.