normal with any new chicken infidel [that is how the girls will see it] whether its a roo or girl.
they need a longer time with getting used to each other,and it is better to introduce them gradualy not in the girls domain.
the poor lad needs a bit of mummying/TLC!
but dont take this as a sign he isnt wanted it is because they have a established pecking order,we had the same issues with introducing new fully grown chickens to an old ex bat,originaly the owner of our residential home put a chuck straight in with her and henny tore her up,they decided she was a chicken hater from that but its because she feels threatened having other chickens come into her dwellings and will react.
same with this poor lad,please get a spare coop for him for now and put that next to theirs, let him get over this for a bit then start to introduce them whilst they free range,this is what personaly do with own chickens and in two playdates have sucesfuly managed to integrate a half a year old pullet within six cochin older chicks-
she is bottom of the pecking order in her group,even though she is perfect with the babies she enjoys having some time out where she is boss.