cmom - that is what I have read that Orpingtons just aren't the best layers. Ironically I read and hear that Australorps are great layers and come from the Orpington breed, with the Australians changing them to fit their needs.
My back up breed, if the feed store doesn't have Australorps, will be RIRs - who I know are excellent layers.
They do tend to go broody more often, almost as much as Silkies, at least mine did. Here is a picture on one of my Buff Orpingtons with her chicks in their brooder.