The effect of body weight manipulation on the concurrent schedule performance of hens

Motivating Operations (MOs) are frequently manipulated (by changing access to commodities and manipulating other variables such as body weight) in order to change the probability of responding. This study aimed to investigate the effect of altering body weight on concurrent schedule performance and to investigate the effect that altering body weight had on the durations of each component of the hens' peck response. Three hens held at 85% ± 5% were shaped via the method of successive approximations and three via autoshaping to respond for food reinforcers on a touch screen. Hens then worked for the same reinforcer under concurrent VI VI schedules across a range of reinforcer ratios with body weight held at 85% ± 5%, 95 ± 5% and 100 ± 5% in separate conditions. Results showed no consistent differences in concurrent schedule performance across body weights, in addition durations of peck components were consistent across body weights.