I have a screamer.

[Dreamalittledream]

I'm assuming the screaming is an unhappy one? Have you tried isolating her? A playpen (with a few age appropriate toys, a blankie from home) really worked for me. When she cries, pop her in and as soon as she stops pop her back out? Perhaps she's overstimulated? Man I wish they came with a translator sometimes. Is there a room just off your play place you could place the playpen? That kind of would give you and your other DCKs a little break on the volume level? Just a thought.

[torontokids]

My cousin's kid started crying one day at daycare for what seemed no reason at all. Their provider got them to pick her up and they brought her to the dr. Turns out she had a broken ankle! Just saying, unless it stops immediately when parents come at the end of the day could be something medical.