4 week old Sebright bantams hen or roo?

[Twinpanich]

Help!! We have three sebright bantams but we are unsure if one is a roo, two of the three are smaller in size and have almost no comb at all, while the third one, (the one furthest right) is larger then the other two and has a comb already coming in. Is it too early to tell or are their signs of a roo?

 

[Tookie]

A bit young to know, but I believe you have 2 pullets and 1 cockerel.