"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.
"a grip, grasp, tight hold," c. 1200, plural, cleches, from or related to the verb clucchen, clicchen (see clutch (v.)). Clutches "the hands," suggesting grasping rapacity or cruelty, is from 1520s.
"movable mechanical coupling or locking and unlocking contrivance for transmitting motion," 1814, from clutch (v.), with the "seizing" sense extended to "device for bringing working parts together." Originally of mill-works, first used of motor vehicles 1899. Meaning "moment when heroics are required" is attested from 1920s.