Can you smell it? Odours and animal welfare

This blog was jointly written by Professor Zhao and Dr Chen Siyu, and discusses the link between farming environment odours and animal welfare. 

Animal welfare is becoming a universal issue all over the world. Animal welfare concerns are not only about humane protection and animal related legislation, but also focuses on societal reaction, scientific research, management, and so on. The assessment of an animal’s health and welfare status has become practical and feasible, and includes behavioral, physiological and environmental judgements.

I have noticed the environmental odours that are associated with animal farms. Strictly speaking, it is actually air pollution. And we have all encountered and felt unpleasant smells in our daily life. A question appears in my mind; could environmental odors be an indicator of animal welfare?

Odours are different between the free-range and caged rearing systems

My team has been studying poultry welfare in China in recent years. We found that indicators of production performance, physiology, gut microbiota and body condition score in chickens were better in free-range than that in caged rearing. However, the most impressive thing to me is that we noticed that environmental odours were very different between the two rearing systems. A strong smell comes to my nose when we’re10 meters away from the cage house and worse pungent smells spring when we first step into the house, yet there is no peculiar smell in the free-range houses.

What drives this difference? It depends on multiple factors, such as density, environment, disease, and so on, but density may be the most dominant factor. Additionally, the intensive indoor systems resulting in crowded conditions and poor welfare causes many other problems to animals, for example behavior inhibition.

Usually, people pay more concern to food safety rather than animal welfare. However, animal welfare is equally important for good animal production and food safety. Would animal products be good if the animals used to produce the products were reared in environments where they experience poor welfare? To answer the question, we need to look into the facts in a different way. We wear masks to attenuate harm of dust smog, even though it may not work. We know halitosis may positively relate to chronic disease from inner system, similarly in animals.

There is a proverb in China, which translates as ‘hearing their voice before seeing the person’, and I hope that the animal farming industry will never be described as 'smelling its odour before seeing it' in a similar way.  We believe that animals experience better welfare when reared in environments which do not have strong odours, compared to environments that smell strongly of ammonia. Thus, the odour level in the farming environment may be regarded as an indicator to assess animal welfare.


* This is a personal blog. Any views or opinions represented in this blog belong solely to the blog owner and do not necessarily represent the views or policies of World Animal Protection.