Chickens are the most abundant domesticated animal with a world population of approximately 23 billion in 2018. With strains bred to produce large number of eggs per year, techniques of rearing and culling might put at risk the welfare of chickens.  Egg-Laying hens coming from commercial hatchery go through hatchery procedures considered as stressful and engaging prolonged stress response in adult chickens. Noisy and dark incubators able to hold thousands of eggs, transportation through conveyor belt, manual sexing and vaccination, are known to contribute to an increase of stress in egg layers chicks and would then be referred as early stress.

The aim of our study was to assess the impact of commercial hatchery procedures on the cognition of the hatchery chicks by evaluating:

1. Their affective state (pessimistic or optimistic) by using cognitive bias protocol
2. Their short and long-term memory by using delayed matching to sample and recalling of the positions of cues.
3. Their need for social reinstatement.

Additionally, we measured the performance of the chicks in tonic immobility and their weight.