Ducks and chickens together

Hi All,
Can anyone help me please...
I have 6 chickens (elsie, sherlie,betsy,dot,blondie and mable) 3 ducks (dafny,jamima and victoria)and a drake (albert), they are all free range in my garden. the problem i have is  albert keeps chasing my chickens and sometimes catches them, i am worried he might kill them, is there anything i can do to stop this..
Also when albert mounts victoria he has started not just nipping here neck but catching her eye and it is a right state - can anyone give me some suggestings on how (if any) i can stop it??
cheers
worried parent

Some people do successfully keep chickens and ducks together but the reason why it may not be a good idea is the drake isn't too fussy - ie it has feathers so do what comes naturally! If you can split them up it may be nicer for the chooks. Although he does sound to be a bit of a goer!