Help! Noisy chickens!

Total newbie here. I have four buff orpingtons that I got at ten weeks old. They are now about 24-25 weeks; started laying 2-3 weeks ago. Eggs are looking good, and chickens all look very healthy.

My issue is that they have become REALLY noisy; not the usual soft clucking, or the announcement of egg laying, but almost shrieking in the morning. It is starting to sound like I'm keeping peacocks. It doesn't go on all day, mostly in the morning, but I'm afraid the neighbors are going to start complaining.

They seem to "want" something; usually they are standing at the gate looking at me in the window while they are screeching. I don't know if it's the food issue. I have been trying to transition them to pellets from crumble for several weeks. They really don't seem to like pellets, even though I've been trying to switch gradually by mixing the two types together. The guy at Agway said they really should eat pellets since they are much more available than layer crumble.

I also don't know if I have encouraged this by running out when they start screeching and throwing in something tasty (blueberries, grapes, favorite weeds,etc)

They have a 12 sq foot coop in an 8' x 12' run., so I don't think they are crowded. I hung a cabbage in there for "entertainment" but they seem to be ignoring it completely.

Any ideas? Why are they so LOUD!