Production systems: free-range vs. intensive

The debate continues over whether free-range birds are more vulnerable. According to Prof. Abolnik, free-range chickens often have lower stress levels and more space to move, which can reduce disease transmission. However, they are more exposed to external pathogens carried by wild and migratory birds, particularly avian influenza. In contrast, intensive systems face internal disease circulation due to high stocking densities, but risks can be minimized through strict biosecurity and vaccination—though even small breaches can lead to outbreaks.

The resilience of indigenous breeds under climate change also remains unclear. “Many believe local breeds are hardier than commercial lines, but there is little scientific data to support this. In my view, they are not necessarily more resilient—although some breeds may suit specific production systems better,” Abolnik noted.

Changing migration patterns and new risks

Climate change may alter wild bird migration routes if food and water sources decline, bringing together species that would not normally converge. This could increase disease spread across poultry populations. Highly pathogenic avian influenza is a prime example of a virus that could spread further under such conditions. Still, Abolnik stressed that global trade, intensive production, and rising food demand pose greater risks than climate change itself.

Importantly, she does not believe climate change will directly trigger new poultry strains. “Mutations arise more from immune suppression or vaccine response, not climate. But environmental changes can create new reservoirs if the original host disappears,” she added.

Prof. Abolnik’s insights underscore a key message: climate change is one of several interconnected factors reshaping poultry health, and producers must balance disease prevention strategies with economic realities.