In order to assess the bird's fear related behaviour towards humans an avoidance distance test (ADT) and a stationary person test (SPT) were conducted.

Both tests are classified as approach tests, with the difference that in the ADT an experimenter applies a forced approach while in the SPT the voluntary approach of the tested animals is investigated by observing the number of birds in a certain proximity to an unknown human. 

The tests were conducted by the same person who was prior to testing unfamiliar to the birds.

The experimental set-up consisted of a defined assessment walk through the house with both stationary and approach phases.

After entering the house, the experimenter walked down one side parallel to the drinking/ feeding equipment at a distance of 1 m, with a speed of approximately one step per second. An ADT was performed at every 6 ^th  to 8 ^th  step, depending on the size of the house (approach of a total number of 40 birds per assessment walk). Every 30 ^th  step a SPT was performed and repeated four times per house at different locations. The tests were conducted by the same person who was prior to testing unfamiliar to the birds.

While walking through the chicken house, every 6 ^th  step the experimenter turned alternative to the left or to the right and approached a randomly selected close individual from a distance of 1.5 m  until the selected individual withdrawed (lifting the 2 ^nd feed from the ground) or was touched.

The distance from the experimenter's hand to the position of the broilers feet prior to withdrawal was estimated (AD).

Results were rounded to the nearest round number, giving an estimation of the AD in 10 cm steps (AD-range: 0 to 150 cm, in 10 cm steps). 

The test was repeated until 40 birds' were approached. If a bird withdraws due to another reason than the approach, the test is stopped and another bird is chosen to perform the test.

To assess the reaction of the birds to a stationary person the experimenter stopped in between the assessment walk and placed herself with the back towards the wall or the feeding line in order to remain motionless. Following, she filmed a defined area (80x 100 cm) in front of her feet, including the tips of her shoes, for two minutes.  Videos were later analyzed by scan sampling, counting the number of birds in the range (at least to 30% inside).