Working for a dustbath: are hens increasing pleasure rather than reducing suffering?

Area of Science:

• Animal behavior
• Ethology
• Animal welfare science

Background:

• Dustbathing is a key behavior in domestic fowl, often restricted by commercial housing.
• Previous research explored the causation of dustbathing but struggled to quantify its importance to hens.
• Determining hens' 'need' for dustbathing substrate has been challenging, using economic and learning techniques.

Purpose of the Study:

• To measure domestic fowl hens' motivation to access dustbathing substrate.
• To compare hens' willingness to work for substrate when deprived versus non-deprived.
• To investigate whether a 'needs' or 'opportunity' model better explains dustbathing motivation.

Main Methods:

• Hens were trained to push open a weighted, swinging door to reach peat moss substrate.
• Two trial series compared maximum door weight pushed when deprived of substrate versus when non-deprived.
• Motivation was assessed by door weight, attempts to open, and subsequent dustbathing behavior.

Main Results:

• Most hens (6/10) pushed more weight when deprived, but overall weight pushed was not significantly higher.
• Deprived hens tended to make more attempts to open the door.
• Significantly more dustbathing occurred after deprivation, indicating increased motivation.

Conclusions:

• Hens show increased motivation to dustbathe after deprivation.
• While willing to work for visible substrate, deprived hens did not necessarily work harder.
• Results align better with an 'opportunity' model (pleasure from behavior) than a 'needs' model (suffering from deprivation).