In Summary
  • Pigs are a good “mixing vessel” for influenza viruses.
  • The workers spend lots of time in the mixed species environment while cleaning and feeding the animals as well as when milking or collecting eggs.
  • Research has shown that chickens, pigs and humans have different influenza viruses named according to the host species as avian influenza virus for chickens and other birds, swine influenza for pigs and human influenza for people.
  • Workers with signs of flu should avoid working with the chickens and the pigs until they have fully recovered.

Majority of livestock farmers engage in mixed farming, where they keep different animals housed together, housed separately or mixing freely while foraging or when they get into their sleeping areas.

Since most of the farming is done for subsistence, the animals kept are in small numbers per household. Many times when I visit such farms, I find chickens looking for beetles and worms in the cattle or pig dung.

Farmers get surprised when I advise them to keep animals separate and they argue that they have always seen the different livestock species mixing without any problem.

“I grew up eating chicken which fed on cattle dung and the cocks were always healthy and very tasty,” a farmer once told me in Kiambu.

This farmer had called me complaining of frequent diarrhoea in his zero-grazed cows despite treatment.

When I visited, I noticed his free-range chickens spent a lot of time in the zero-grazing unit pecking at the cattle feeding troughs for dairy feed morsels. The troughs were littered with chicken droppings, some of them watery.

I treated the cows and the chickens for bacterial diarrhoea and advised the farmer to separate the birds and the cattle since latter were transmitting bacteria that caused diarrhoea in the former.

The problem was resolved when he complied with my advice.

In the last two weeks, some farmers have asked me whether various livestock species can be mixed to increase the efficiency of production.

Some argue that it is easier to manage the animals when they are mixed or close together.

Farmer Gichana asked whether he can mix chickens and pigs, while Kamau wanted to know if he can house chickens on top of his zero-grazing unit to manage the little space he has.

The questions have logical considerations, but then disease-causing organisms do not understand the convenience of the farmer.


To them, mixing livestock, and in such confined spaces, provides the microorganisms with a perfect opportunity for host diversification.

We all love diversity because it widens our survival options. The disease microorganisms also “understand” the benefits of diversification.

Remember that as we mix the livestock species, we normally forget that the human being is also in the same mix as he takes care of the animals.

The workers spend lots of time in the mixed species environment while cleaning and feeding the animals as well as when milking or collecting eggs.

There may be little or no problem when only small numbers of animal species are mixed but when this involves several animals, the likelihood of cross infections or incidents of disease organisms jumping species increase.

Jumping species is the term used when a disease organism that normally infects one species adapts itself to cause disease in a new species.

Let us look more closely at Gichana’s question on whether he can mix chickens and pigs on the same farm.

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