McBride, 1969, The social organization and behaviour of the feral domestic fowl, Anim. Behav. Monogr., 2, 125, 10.1016/S0066-1856(69)80003-8
Treisman, 1975, Predation and the evolution of gregariousness. I. Models for concealment and evasion, Anim. Behav., 23, 779, 10.1016/0003-3472(75)90106-2