10 week old cockrel question?

[4acresNachick]

I started out with 9 RIR chicks that I raised from 1 day old. 5 I gave to a family whose current layers where getting old, out of the 4 left 1 turned out to be a boy. He is by far the friendliest but I ordered all pullets and was not planning on keeping a roo. Now for my question. How old do they have to be to start reproducing? I put him and the 3 pullets together with my 4 1yr old hens and after about 2 weeks he started trying to mate with all the older girls. He is almost 11 wks old and I am wondering when he could start fertilizing eggs. If I don't want that does he need to be separated? I am still undecided about having a roo at all so when I saw that I couldn't believe my eyes. I guess I'm still thinking of him as the little chick in the brooder but I obviously has other ideas

Any help or advice would be great. Thanks!

 

[ck-newbe]

I searched how old to fertilize eggs in this forum and I found a thread that said somewhere between 16 to 18 weeks.