Red Mites and Autopsies

Reading Time: 4 minutes

Guda van der Burgt is a veterinary pathologist who undertakes chicken autopsies. She lives at Rough Ground Farm in Oxfordshire, England, and keeps chickens with her husband, Patrick.

“We have bluebell chickens, a hybrid breed,” she says. “We recently bought them a new coop because the old coop was infested with red mites, a persistent problem, and we wanted to get rid of them for good. But the new house was too small and was not correctly described by the seller. He said it was suitable for 5-9 birds, but it wasn’t. The chickens stopped laying eggs because the house was too small, so we had to get them another coop and we received a refund from the seller.

“We started keeping these hens just before lockdown in 2020. We bought a flock of five hens. The hens were 19 weeks old at the point of lay, which means they’re at the age where they start laying eggs. They started laying on their first day with us, and one hen laid her first egg in the car on the way home!

“We feed them a mix of layer pellets and mixed corn. One of the chickens became ill within a week and died due to an impaction. I guessed this was because the previous owner had fed them meal, which doesn’t need grit to aid digestion. I’d switched their diet to corn, and they needed a source of grit to digest it because it was a change of diet. As soon as I realised what the problem was, I put a shovel load of little stones and grit into their enclosure and the rest of them recovered.”

A Battle With Red Mites

The couple have had an ongoing battle with red mites. Guda explained: “To treat these infestations we use Diatomaceous earth, a sharp powder that kills red mites. That helps us keep on top of it but it’s been an ongoing battle.

“You can treat the hutch with nasty chemicals but we prefer not to. Wooden coops are more prone to mite infestations because they hide in the wood, then come out at night and get onto the chickens, underneath the wings, everywhere, and they make them bleed and lose feathers. The birds stop laying and start itching. They lose blood because the mites feed on their blood. It’s horrible. That’s why we recently decided to switch to a recycled plastic coop.”

I wondered if there was merit in leaving Diatomaceous earth for them to bathe in, but Guda explained why that doesn’t work very well. “It’s not practical to leave diatomaceous earth in the hutch all the time because when it gets wet it turns into a paste.

“Fortunately, we’ve got rid of the red mites for now. We treated the hens with an injection. The new coop should help keep them free from mites going forward, so we’re hopeful that we won’t be revisiting this problem!”

A Post-Mortem Vet

Guda works as a veterinary pathologist. “It may seem bleak to be doing autopsies at work, but it’s always useful to know why an animal dies, so you can take preventative action to improve the animal’s health in future,” she says.

“We keep the chickens in a pen in a field. The pen protects them from foxes and other predators. We move the pen every few weeks, which helps with worm control and reduces the risk of other parasite infestations. It also gives them fresh ground to dig and forage.

“We can treat them for worms and other parasites but we don’t want to use anti-worm medication more than necessary because of its adverse effect on wildlife and insects. Many treatments are harmful to earthworms and insects as well as mites and parasites, so we prefer to use natural methods of parasite control. It’s been shown that popular anti-worm treatments used in sheep kill earthworms and dung beetles, and slow the growth of grass.”

As a veterinary pathologist, one of the most common causes of death Guda sees in chickens is egg peritonitis. “When an egg is laid, it gets caught by a funnel-type structure and goes into the oviduct – a tube to the outside. If the funnel doesn’t catch the egg it ends up in an abdominal cavity and causes inflammation. The shell is created in the oviduct, so there’s no shell, but just the trapped innards. This can kill the bird. The second most common cause is parasites, such as worms and coccidia.

“Chickens also get Marek’s disease sometimes – a virus that can cause cancer. Commercial hens are vaccinated against it, so it only tends to affect unvaccinated backyard chickens. That’s one of the benefits of adopting ex-commercial laying hens.

“We’ve had other chicken breeds in the past too – we had Light Sussex, Buff Orpingtons and commercial hens from a local chicken farm. They lived up to 10 years old, which is good for a hen because often they get predated.

“The weirdest cause of death I’ve come across in my work was when I was contacted by the local police to investigate the case of a dead hen, who’d been killed by a man having sex with chickens. One of the birds had a piece of string tied to her leg and a used condom in the pen. I don’t know whether he was prosecuted, but my findings formed part of the police report and investigation.

“A lot of the causes of death are parasites though and viral diseases like infectious laryncheal tracheitis.”

Enjoying Freedom on the Farm

“The birds do enjoy their freedom on the farm. I like letting the birds out every morning. We used to have tenants with five dogs in the old farmhouse, and we were worried that if we let the hens roam free in the mornings that the dogs would get them. But now the dogs are gone, so we feel it’s safe to let the hens out in the daytime. I let them out every morning and they’ve been enjoying roaming free every day since the tenants left.

“We don’t name our hens, but the cockerel is called Monty, short for Montgomery.”