Completely depends on the cockerel... I have had them as early as 3-4 weeks and as late as 38+ weeks. At that age they aren't roosters they are cockerels and you can't count on them for a LOT of things.
The terms rooster and hen are saved for after they reach one year old. Prior to that cockerel or pullet is accurate. We still use it slang around my house... but when it is important to note the difference is anything behavioral... cockerels are a WHOLE other animal than a mature cock. (which is the only accepted term when showing adult males just for informational purposes)
Once birds reach a certain age... usually around 12-14 weeks they start to develop gender specific feathers. Your white boy is currently not the dominant one... but as he mature he may challenge for the position. Once they are coming in saddle feathers do NOT lie (except on Seabrights).. Your white boy will not be laying any eggs, ever...So there's a chance? Or for sure this is a rooster?
Some people are successful at keeping more than one boy... I generally don't recommend keeping ANY boys for new owners... hen flock really are more peaceful. Then once hens are mature and you got some time under your belt... maybe you would like a rooster!
I keep a stag pen... but it has it's challenges.
Good luck, whatever you decide!
