Oyasumi, Itoshii Kotori-sama

Despite disliking the haughtiness of winged people, Shuu begins work at a winged person's manor doing miscellaneous chores. He meets Rai, a winged person who is the head of the manor he works at and is rumored to be hard to deal with. Shuu winds up in an awkward situation where he's told by Rai that he has to "incubate the egg".
A developing romance in a world where "winged people" and humans co-exist.
(Source: Daria, translated)
Note: Includes an extra chapter.