Behavioural estimates of auditory thresholds in hens.

Six hens were trained in a trial-by-trial auditory discrimination in which trials were signalled by the lighting of two key lights. Correct responses (left-key pecks when a tone was presented and right-key pecks when it was not) produced intermittent deliveries of food. Following training at one tone frequency and intensity, testing sessions at lower intensities were carried out. Training and testing were repeated for 10 frequencies between 260 Hz and 8000 Hz. Derived measures of detection performance allowed estimates of the intensities at which no discrimination would have occurred. The threshold measures are presented and suggest that the range of most sensitive hearing was between 3000 and 5000 Hz.