How to curb screaming?

I have mostly girls (my first mistake) but they have taken to screaming lately. We are talking screaming about everything; when they are happy, sad, angry, hurt etc and it is driving me crazy. How do I curb this behaviour? Currently I redirect with "use your words," "no screaming," we have been hatching chicks so I have used this as well "we need to use quiet voices so the chicks can hatch" etc. Help! It doesn't seem to be getting better. I have even been putting them on time out for those horrible/unnecessary, screaming just to scream screams. Argh!

My dcks, boys and girls would start screaming when they were waiting for me to plate their food. I told them that there would be no food coming till the screaming stopped. Someone always seemed to get the screaming started, so I've tried miss outs (not on food though) for the instigator. He/she can re-join the group when they quiet down. I've also ignored all 5 of them screaming too, as i thought they're just trying to get a rise out of me. so they screamed until their voices were hoarse, whilst i yawned a pretended to read a book.... they didn't bother much after that... no point in screaming if it doesn't bother me. It comes and goes, and does get on the nerves. I did find though that if I gave a miss out to the 'starter', some of the other kids would quietly try to get him to start screaming first so he'd get a time out.... sneaky huh!! If things are too noisy i usually say we won't be doing such and such until things are settled down again. I also tried joining them once, screaming/laughing eyes rolling around and tongue flapping out...not a cute sight at my age, so they stopped then too. Good luck!

Thanks for the advice. I think I'm partially more sensitive to the screams as my new neighbours (sharing a wall as I am semidetached) moved in a few days a go. I do not want the daycare to be a problem for them.