Putting new pullets in with mature rooster

I already have hens and a rooster, however I have a group of young pullets (7 weeks old).  When shoud I put them in with my mature rooster?

hi  i have  put pullets in at around 10 weeks or so depending on the breeds, if you have  banty pulltes and a LF rooster maybe wait a little longer. i currently have 2 pullets and a boy aged 12 to 15 weeks is and they are still seperate at night as they are banty size and my big boy  :oops:  is a sussex they all mix in the day tho........ to get used to each other.
hope that helps