Sentence:  The events of the last quarter of an hour , mysterious to any <WSD>bird</WSD> accustomed only to the predictable life of coop and barnyard , had overcome the doctor 's hen and she gave out a series of cackly wails , perhaps mourning her nest , but briefly enjoyed . 
Meaning of the word marked with <WSD> tags:  warm-blooded egg-laying vertebrates characterized by feathers and forelimbs modified as wings