New one... chicks picking on the pullets

(btw, when do pullets become hens???)

My 7, nearly 8 week old roos are picking on my pullets.  Not often, but when they do they really go for it.  Last night Tach' had hold of Onions wing and was not letting go.  I squirted him with the hosepipe (maybe a bit OTT, but he certainly got the message!)

Both roos are bigger then the pullets now (even at their tender age!).  Will it just settle down over time?  I only took the chick pen down 5 days ago. The chicks and pullets sleep in different coops, but I had hoped to get them all intogether at some point.