IMPORTANCE OF TACTILE AND VISUAL-STIMULI OF EGGS AND NEST FOR TERMINATION OF EGG-LAYING OF RED JUNGLEFOWL

Experiments were conducted to separate the influence of tactile and vi sual stimuli emanating from the nest or eggs on the development of inc ubation behavior, the termination of egg laying, and the determination of clutch size. Red Junglefowl (Gallus gallus spadiceus) hens, whose eggs were left inside the nest (experiment 1), received both tactile a nd visual information, remained in the nest box longer, and stopped la ying after eight days (or six eggs). Sixteen or 17 females incubated. Leaving only the first egg in the nest (experiment 2) gave similar res ults. When the eggs laid were placed under a wire-mesh basket (experim ent 3) such that the hen could see but not touch the accumulating eggs , laying stopped two days (or one egg) later than in experiment 1, and most hens ''incubated'' on the empty nest until the nest box was remo ved. Surprisingly, when eggs were continually removed (experiment 4), hens also incubated progressively more, stopped laying after two weeks (or nine eggs), and then sat on the empty nest for one or more days. Stimulation of the brood patch by the nest alone led to more incubatio n and to termination of egg laying. Visual stimuli alone provided by e ggs accelerated both processes and were sufficient for one-half of the hens to maintain full incubation behavior. Red Junglefowl do not appe ar to judge clutch size visually.