Diary of a poultry farmer: For healthy birds, always deworm your chickens

Wednesday March 18 2020
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Louise Ndung'u feeds her 450 layers at Salama, in Elburgon. For ideal poultry production, ensure the chicken are free from worms as these can cause severe damage to the birds’ gut or airway leading to anaemia, bleeding, loss of nutrients and toxicity. PHOTO | JOHN NJOROGE | NMG


Last week, when I got a ‘please-call-me’ message from Emmanuel, my farm worker, I assumed that he was calling to remind me to send him money to buy vaccines, or he needed a salary advance. I was wrong on both fronts.

“Please come with that medicine you brought last week,” he quipped.

You see, for the last two months, I’d been hatching my own chicks and the two batches still in the brooder box were due for their second Newcastle and first gumboro vaccination at day 21 and 14 respectively.

When I mentioned that the booster vaccines were not due until the following day, he said, “I meant the medicine you told us to give in water and to then discard all the laid eggs from the batch for the following three days,” he said.

Okay, I realised he was talking about the drug I’d used to de-worm the chickens. Worming chickens and other poultry is something I do routinely on my farm, first at point of lay and then every three months throughout the life cycle of the laying hens.

What Emmanuel had observed was a drastic increase in egg production in one batch of 31 hens from an average of three the previous week to 25, giving a hatch rate of about 80 per cent.

Some background here. I learnt from the good vets that de-worming chickens is just as important as vaccinating them because most infestations by worms can cause severe damage and even death in the flock.

“Worms can cause severe damage to the chickens’ gut or airway leading to anaemia, bleeding, loss of nutrients and toxicity,” one expert told me.

Another thing I learnt was that one can’t pick out worms merely by looking at the chickens’ droppings.

“Looking out for worm eggs is problematic because the eggs are too small to be visible with the naked eye and have to be identified under a microscope,” he said.

In fact, even inspecting droppings regularly is useless unless there are large numbers of worms.

I also read that there are two groups of parasites, ecto and endo. Ecto-parasites are found on the outside of chickens’ body and examples include lice or mites.


On the other hand, endo-parasites are found inside the bird and are referred to as helminths. The most important of which are called nematodes that inhabit the chickens’ digestive tract.

Another thing is that there are two ways in which chickens can pick worms from their environment. In the first instance, an infected chicken expels worm eggs by their thousands in droppings.

The eggs can survive in the ground or coop for up to a year before being picked up by foraging birds and this is called the ‘direct life cycle, the vet intimated.

In the ‘indirect life-cycle’, the worm’s eggs are expelled from an infected bird by their thousands in the droppings and enter intermediate hosts such as earthworms, snails or centipedes.

When the chicken eats the intermediate host, it ingests the worms’ eggs that then hatch into larva in the chicken’s body and the cycle of infection is repeated.

I also learnt that the most common symptoms of worm infestation are loss of weight — or poor weight gain — increased feed consumption, pale egg yolk colour, diarrhoea and in severe cases, anaemia (pale comb and wattles) and mortality. In the case of gapeworm, chickens will gasp for breath or ‘gape’ stretching their neck.

Now, Emmanuel was disappointed when I told him we can’t repeat the de-wormer after two weeks. The vets advise that if you’re de-worming as part of prevention routine, repeat at least every 3-6 months.

Now, if you see worms expelled in droppings after treating your birds, you need an ongoing treatment plan, because although the initial treatment kills the worms in the body, it spares the eggs on the floor or on the run and in the intermediate hosts such as slugs, snails and earthworms.

To safeguard human health, eggs and meat should not be consumed for three days and seven weeks respectively after administering any antibiotic to poultry and this also applies to de-wormers.