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Tackling Northern Fowl Mite and Preparing for Rearing Season

Dr Kenny Nutting BVetMed MRCVS St David’s Game Bird Services 

In our latest monthly feature, Dr Kenny Nutting BVetMed MRCVS of St David’s Game Bird Services will be writing ‘The Vet Diaries’, covering everything from husbandry, veterinary health plans and game bird management to industry updates, preventative planning and disease updates. 

We are seeing Northern Fowl Mite in a number of laying stock, both overwintered and caught up birds, with incidence in much higher numbers than I have seen for several years. We are seeing these cases mainly in pheasants, and it seems to effect partridges significantly less. The mites seem to be more attracted to cock birds and in the smaller strains of birds.

The Northern Fowl Mite (Ornithonyssus bursae), is an oval shaped mite about 1mm in size. Like the Red Mite, it starts off life a pale grey colour and feeds on the bird by sucking its blood, turning the engorged mite a black/brown colour. This feeding causes irritation to the bird, which often results in increased stress and a subsequent drop in egg numbers. It is important to identify the type of mite you are seeing on site to ensure you use the correct products to eradicate them. My tip to keepers would be that the Northern Fowl Mite is easily distinguishable and seen on the birds in daylight, whereas Red Mite are more commonly seen on the birds in the night time, so checking during the day is a good way to tell the difference between the two.

There are a range of options to prevent and eradicate mites such as Exzolt, which has been successfully used in game farms in the US and here in the UK. This is a prescription medicine so if you are having problems with mites please speak to your vet about your options. When prescribed, Exzolt is often used in two courses, a week apart, in order to break the life cycle of the Northern Fowl Mite and is extremely effective. This products use is off license and thus should be discussed with your vet for specific guidance.

In April, the pheasants are reaching peak lay and this is usually when we start to see the early indications of deformities and eggshell quality which can begin to dip slightly. During this time last year, I was working closely with a site which had some issues with eggshell quality, so we used a product called 50 Week Plus to provide additional calcium supplements to support the birds during this period. This resulted in the number of graded out eggs reducing from around 15% down to just 3% after using the product for 48 hours. The product ingredients include calcium, magnesium, zinc and other vitamins and minerals that work to provide the bird with the correct mineral ratio, supporting overall egg production and encouraging shell formation and strength.

As 50 Week Plus is a supplementary liquid it is very easy to administer to the birds via their drinker system, and for best results we would recommend using a product called Aqua-clean to help to clean and disinfect the drinker lines. This is particularly important as dirty or contaminated water can destabilise the gut health of the bird and compromise the efficacy of supplements given in the water.  

At St David’s, we work nationally so hear updates from regions across the UK. Matthew Balfour BVM&S MRCVS of St David’s Game Bird Services in Scotland noted, “Shoot days are rapidly booking up on many estates and poult orders are strong. Unfortunately, a shortage of bottled gas is causing logistical issues on some sites. – we’ve written a brief article on the gas shortage and bulk tank solutions, please find this on our website. Many sites are currently reviewing their cleaning and disinfection protocols with a particular focus on reducing the early coccidiosis challenge in sheds.”

To speak to our team for further advice or information please visit or give us a call on 01392 872932.

Originally written for Countryman’s Weekly – April 21