a guy who has smallpecks or does not have pecks or a girl who has small or no boobs
my boyfriend and i were sitting in a car where someone shouted, "look at chicken chest sitting there." i was not sure if he was talking about my size A boobs or my boyfriend's chest.
A chicken chest is a reference to a male that has worked out his upper body so that he has massive pecs and biceps and etc., but has forgotten to work out his legs, which remain skinny and frail-looking. In short: huge chest, skinny legs, like a chicken.
Andrew loves to bench press, but hates leg presses; that's why he has a chicken chest.