I have 4 hens that are making that annoying noise right now. They were so loud yesterday I had to go down to the coop to make sure nothing was wrong. At the moment it's my 3 australorp and 1 salmon faverolle. Hopefully we'll be seeing eggs from them soon!!
My mother has a hen who does this ALL the time. She is HUGE, has a deep, masculine sounding voice, and is named Princess. LOL She does that before she lays an egg, before someone else lays an egg, if another chicken does something she doesn't appreciate (like eat a nice juicy bug). If you pick up a chicken besides her she will stand at your feet staring up and making that sound at you. We consider her the big boss. LOL I told my mom I was going to steal her the other day and got an "over my dead body" reaction. We all think it is adorable!!!!
My girls make that noise and usually I find a gift in the box not long after. It is really funny when two are a box together singing(if you can call it that) their duet.