Sentence:  The events of the last quarter of an <WSD>hour</WSD> , mysterious to any bird 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:  a period of time equal to 1/24th of a day