Rear Sprocket Squeaking
 

The rear sprocket on my new Specialized Roubaix is making a squeaking noise that sounds like a nest of baby birds. I’ve brought it back to the shop I bought it from and the tech said when he road the bike he couldn’t hear anything. He lobed it up, but it is still squeaking. Any ideas what the problem could be? Thanks.

Rear derailler jockey pulleys need some grease.