1762, said to be a reference to John Montagu (1718-1792), Fourth Earl of Sandwich, who was said to be an inveterate gambler who ate slices of cold meat between bread at the gaming table during marathon sessions rather than get up for a proper meal (this account dates to 1770). It was in his honor that Cook named the Hawaiian islands (1778) when Montagu was first lord of the Admiralty. The family name is from the place in Kent, Old English Sandwicæ, literally "sandy harbor (or trading center)." For pronunciation, see cabbage. Sandwich board, one carried before and one behind, is from 1864.
Old English cicen (plural cicenu) "young of the domestic hen, the young of any bird;" by early Middle English, "any chicken," regardless of age, from Proto-Germanic *kiukinam (source also of Middle Dutch kiekijen, Dutch kieken, Old Norse kjuklingr, Swedish kyckling, German Küken "chicken"), from root *keuk- (echoic of the bird's sound and possibly also the root of cock (n.1)) + diminutive suffixes. By regular sound changes it should have become Modern English *chichen; the reason it didn't is unknown.
Generic words for "chicken" in Indo-European tend to be extended uses of "hen" words, as hens are more numerous than cocks among domestic fowl, but occasionally they are from words for the young, as in English and in Latin (pullus). Meaning "one who is cowardly or timorous" is from 1610s; adjectival sense of "cowardly" is at least as old as 14c. (compare hen-herte "a chicken-hearted person," mid-15c.). As the name of a game of danger to test courage, it is first recorded 1953.
Chicken-feed "paltry sum of money" is by 1897, American English slang; literal use (it is made from the from lowest quality of grain) is by 1834. Chicken lobster "small lobster," is by 1947, American English, apparently from chicken in its sense of "young." To count (one's) chickens before they hatch "anticipate too confidently the obtaining or doing of something" is from 1570s. Chicken-fried steak (1937) is a U.S. Southern recipe that batters, breads, and fries a thin strip of steak in the way fried chicken typically is made.
type of hawk that is believed to prey on domestic fowl, 1802, American English. Figuratively, from the secondary senses of both words, "public person who advocates war but declined significant opportunity to serve in uniform during wartime," at least 1988, American English. From chicken (n.) + hawk (n.).
"the young of a chicken or domestic fowl," mid-15c. (early 14c. in surnames), a contraction of Middle English pulte, itself a contraction of polete "young chicken" (see pullet).