Both male and female day-old chicks were categorised as high latency (HL), moderate latency (ML), or low latency (LL) based on their latency to peck pebbles. The latency of the HL category decreased with anxiolytic doses of diazepam, a drug designed to reduce fearful behaviour and release suppressed behaviour, but the latency did not decrease in the ML or LL treatments. This data suggests that HL chicks were the most anxious. In an open-field test, the 15-day-old LL chicks showed the lowest latency to walk. They showed the lowest immobility duration in the tonic immobility test, and they showed insensitivity to anxiolytic doses of diazepam in both behavioural tests. Their insensitivity to diazepam suggests that the 15-day-old LL chicks were the least anxious. The increase in the density of the central benzodiazepine receptor (the receptor that binds with diazepam) induced by acute stressors was highest in the most anxious and/or fearful HL group. Since there were more females in the LL category, and more males in the HL category, the data suggest that the fear pattern depends on the sex and inter-individual differences within a same sex, which are stable across life. This test could be a useful method for determining fear and/or anxiety state, and useful for choosing birds with the best performance later in life.