help - new chickens are causing old ones to make so much noise!

Hi all, we have two established hens, a bluebell and a white chicken which get on fine together....

Last week we got two new hens, for the first couple of days there was a lot of squawking from the existing hens, we let them free range together and put them in a pen with a divider between them for a couple days so they couldn’t attack each other, but letting them sleep in the same coup at night

the problem we have is that the two groups of chickens are fine with their respective partners, but the older existing flock is very aggressive towards the new comers sometimes chasing them around the garden, pecking at them etc - which is fine as it’s all part of the pecking order etc. but the actual main issue is the amount of noise that the bluebell is making, for some reason as early as 5 am we hear her squawking very loudly. it’s the bwark bwark bwark bwark BERQUAK type sound which is really annoying to us and of course to our neighbours...so we have been getting up at 5am to let them out to free range for a bit before work which seems to calm it down a bit - but then it still does which has us rushing into the garden to shut it up...what can we do to try to calm it down...we can’t go on like this due to the noise being generated. Heaven knows what’s going on while we are at work!

It’s been a week now and things haven’t really improved, the bluebell is still squawking and clearly the neighbours must be getting really irritated by this. Please if you have advice im willing to try it