cluck (v.)

"a brood, the number of eggs incubated at any one time," in reference to chickens, 1721, a southern England dialectal variant of cletch (1690s), noun from cleck (v.), which is from Middle English clekken "to hatch, give birth to" (c. 1400), which is probably from a Scandinavian source (such as Old Norse klekja "to hatch"), perhaps of imitative origin (compare cluck (v.)). Compare batch/bake.