when you wean them all together with the hens all the hens feed all the yb's so as long as the younger pair are calling to be fed they will get fed. Also last thing in the evening after weaning check there crops are full and if not top them up by hand for a couple of days.
Its getting worse all the time, beyond a joke when you can't even let the birds excercise without being in constant fear of attack!
Hope more return for you then lock them up for a couple of days to get them settled.
If you are going to just run an extension then buy yourself a caravan hook up cable if its going to be left outside as they are waterproof.
But best to take above advice and get an electrition to put you a seperate circuit/ring outside then you know it will be safe and you won't risk overloading it.