This study used 53 individuals from an advanced inter-cross of Red Junglefowl and White Leghorn as the model organism. Prenatal maternal stress was artificially induced by inserting either a 7.5 mg corticosterone (CORT) pellet or a placebo pellet under the mother hen’s skin. Thereafter, 12 days followed, during which the hen’s eggs were collected and stored until the offspring hatched. The offspring later performed two behavioural tests: the Open Field test and the Emergence test.
Open Field Test
One by one, each test subject was placed in an open arena (as seen in the video below), which had two regions of interest: the inner zone and the outer zone. They were recorded for five whole minutes, and the obtained videos were later analysed by artificial intelligence (AI). The data from the AI were thereafter analysed in R.
Emergence Test
For the emergence test, we used an adaptation of Jones and Mills’s (1993) “Hole-in-the-Wall” box test. The test was over when the test subject had fully emerged from the box (max 5 min), as can be seen in the video below. The videos were analysed by using a Cox proportional hazards model in R.