Ontogenetic development of conditioned food aversion in chickens

Area of Science:

• Animal Behavior
• Avian Physiology
• Learning and Memory

Background:

• Neophobia, an innate avoidance of novel stimuli, is a crucial survival mechanism in young animals.
• Conditioned food aversion (CFA) is a learned response where an animal associates a specific food with a negative experience, leading to avoidance.

Purpose of the Study:

• To investigate the developmental changes in conditioned food aversion (CFA) and neophobia in Leghorn chicks.
• To determine how age influences the mechanisms of food aversion learning and its protective role against poisoning.

Main Methods:

• Leghorn chicks of 25, 35, and 45 days old were used to study CFA development.
• Food-deprived chicks were exposed to a novel colored food (CS) followed by a lithium chloride injection (US) or saline control.
• Food intake and pecking behavior were measured to assess neophobia and CFA retention.

Main Results:

• 25-day-old chicks exhibited significant neophobia towards the novel food, which was enhanced by CFA.
• 35- and 45-day-old chicks showed less neophobia, but CFA was clearly demonstrated in the older experimental group.
• CFA in younger chicks primarily involved inhibition of pecking, while older chicks also reduced peck volume.

Conclusions:

• The primary mechanism for protection against poisoning in chickens shifts from neophobia to CFA between 25 and 45 days of posthatching age.
• Age-dependent changes in learning and behavioral responses influence the effectiveness of different anti-predation strategies in young birds.