Red Mites in Backyard Poultry

Posted by on Oct 8, 2018 in Uncategorized | No Comments

With the modern worry about food miles and unauthorised additives in our food, it’s no surprise that the numbers of backyard chickens are soaring! However, with those increased numbers of little flocks come a few problems – especially, people who now own a few hens (which is great!) but haven’t got much experience with their ailments. In this blog, we’re going to take a look at one of the most frustrating of conditions to manage in poultry – Red Mites.

What are red mites?

Red mites are small (usually a little under 1mm), red creatures quite closely related to spiders. Their technical name is Dermanyssus gallinae, and they live by sucking blood, primarily from birds (although if they’re hungry enough, they will feed on other animals, including humans!). Unlike their cousins the Northern Fowl Mite, Red Mites do not live on the birds. Instead, they hide away in crevices in the house and come out at night to feed.

How do they live?

Female mites mate and then lay a clutch of eggs. The eggs hatch into larvae (like maggots) in crevices in the house, which then grow into “baby” mites (“protonymphs”). These come out to feed on your birds, then moult into “teenage” mites which again feed, and then develop into adults. The adults mate, and repeat the cycle; a female can lay several clutches of eggs, although she must take a fresh meal every time. In warm weather (e.g. in the summer), the cycle can complete in less than a week! And the mites travel too – on wild birds and also on rodents such as rats. This is why a flock
may have no problems for months or even years, and then suddenly develop a massive infestation.

What do they do to my hens?

The mites lurking in the house aren’t the problem – the trouble is that they’re sucking on the hens! There are three major symptoms of an infestation:

● Bloody spots or streaks on the eggs, as a few blood-gorged mites were squished when the egg was laid.
● Irritability and pecking – the mites irritate the birds, making them more prone to peck; however, if the birds see a mite on another hen, they’ll peck at it, so you can rapidly develop a major feather-pecking, vent-pecking or even cannibalism problem.
● Anaemia in the birds – this is usually mild, but can be so severe that the comb and wattles become pallid and white, and may even in extreme cases be fatal!

You won’t usually see mites on the birds – however, in heavy infestations it may happen, and you’ll certainly be able to see the mites in the house: if you shine a torch into a dark corner, you’ll see them running to escape the light.

How can I kill them?

Well, the good news is that in most situations, you don’t need to put any pesticides on the birds. If you can get the birds out of the house in daylight, then you can clean the house and kill the mites.
The first step is to remove all the contaminated bedding, and then apply a cleaning solution or spray. The traditional treatment of choice was creosote; however, that was actually really quite toxic to humans and hens, so it has now been banned. There are a range of other, similar compounds available though – the most popular are probably Interkokask spray and Poultry Shield. These should be applied fairly liberally to the inside of the house, especially the dark crevices where the mites hide. These will not, however, kill the eggs, so should be repeated three times about a week apart to make sure that all the mites, larvae and eggs are dead. Another option for mild infestations is to use diatomaceous earth – this is gritty on a microscopic level and is harmless to poultry and people, but lethal to mites as it abrades their skins and dehydrates them. In fact, it’s useful to add this to your replacement bedding (usually about 30-50g per square metre).

Do the hens need any treatment?

This isn’t usually necessary; however, diatomaceous earth can be applied to the bird directly (sprinkled over the vent and under the wings, then rubbed into the feathers), or supplied in the dust bath so the birds self-medicate In the most severe cases, ivermectin based pesticides can be prescribed by our vets (they’re off-license so it isn’t something you can legally do without a prescription in egg- laying birds) to clear the mites off the birds, although remember that eggs will be unsafe for a fairly long period afterwards, usually at least 4 weeks, if not longer. A hen who is severely anaemic may need additional amino acids and vitamin and mineral supplementation – talk to us for advice if you’re concerned.

Can I stop them coming back?

Regular use of diatomaceous earth is good, but ultimately, the only way to stop them coming back is to stop any animals or birds carrying them back! So make sure you have a good anti-vermin programme to keep rats and mice away, and if possible mesh off the run so that wild birds can’t infect them.

If you’re concerned about any of your hens’ health, give us a call and speak to one of our vets for advice. A lot of problems can be sorted with advice over the phone, but if not, we’re more than happy to see you and your birds!