Chicken Health and Vet Care: Worms, Mites and When to Call a Vet

Beyond predator-proofing, day-to-day flock health has its own checklist — worming, parasites specific to chickens, and the behaviour changes that mean a call to the vet. This guide sets out what animal welfare guidance says, and is clear about what it doesn't cover.

Worming: regular, not just when something looks wrong

The RSPCA recommends regular worming, particularly for flocks kept in the same outdoor area for more than a month, since droppings can build up and re-infect the same ground. Rotating to fresh grazing where possible helps reduce reinfection between treatments. RSPCA, pet chickens.

Three worm types, and what they look like

The RSPCA names gapeworms (live in the trachea), tapeworms (attach to the intestinal lining) and roundworms (inhabit the digestive system) as the worms to watch for. Signs include reduced egg production, diarrhoea, lethargy, increased appetite, and — in severe cases — weight loss. The RSPCA is direct that a serious infection can be fatal if left untreated.

Lice and red mites: different parasites, different seasons

Lice (2–3mm) live beneath feathers and lay eggs on the feather shafts; signs include scratching, sore skin, feather loss or damage, and overpreening. Chickens often suffocate lice themselves through dust bathing, though a chicken-safe louse powder added to a dust bath helps with larger infestations. Red mites are smaller, found under wings or hiding in the coop rather than on the bird, and cause reduced egg production, a pale comb or wattles, and other signs of anaemia. Both are more commonly seen in summer; the RSPCA notes plastic coops make it harder for red mites to settle in, compared with wood.

Feather pecking: a symptom, not just bad behaviour

Feather pecking — hens pecking and pulling at other hens' feathers, typically around the back and vent — isn't random. The RSPCA names several contributing causes: environmental factors, nutritional deficiencies, poor health, pecking-order stress, and sudden changes to the flock or its surroundings. Prevention leans on the same things good flock management already covers: gradual changes rather than sudden ones, visual barriers and enrichment, a proper diet, multiple feeders and drinkers so birds aren't forced to compete, and watching flock health regularly enough to catch a cause early.

Avian influenza: a handling caution

The RSPCA advises against touching or handling sick or dead birds where an Avian Influenza Prevention Zone is in effect, and to wash hands thoroughly if contact does happen — a caution worth knowing even outside an active outbreak period, since guidance can change with local conditions.

What to watch for day to day

The RSPCA lists hunched posture, erect feathers, head tucked under the wing, hiding, dirty feathers, lameness, runny droppings, and discharge from the eyes or nostrils as signs that warrant veterinary consultation — a useful daily checklist since most of these are visible from a normal coop check, not something that needs special equipment to spot.

If you're hatching your own

Raising chicks from an incubator adds its own health considerations before they even reach the flock — see our guide to how long a chicken egg takes to hatch for the humidity schedule and when to move chicks to a brooder.

What this guide doesn't cover

This is general information from a single welfare-body source, not veterinary advice, and it doesn't replace a vet who knows your own flock. The RSPCA's page didn't cover vaccination for pet chickens specifically, so we haven't included it here rather than guessing. For routine health costs, see our cost guide, and enter your own vet's quote into the cost of keeping calculator. A sudden drop in egg-laying is often the first sign something's wrong — see our egg-laying guide for how to tell a health issue apart from a normal seasonal or molting slowdown.

Source: RSPCA, “Pet Chickens”: rspca.org.uk. Sources checked: September 2026. General information, not veterinary advice.

Common questions

How often do chickens need worming?

The RSPCA recommends regular worming, particularly if hens are kept in the same outdoor area for more than a month, since droppings can re-infect the same ground. Moving them to fresh grazing periodically helps prevent reinfection between worming treatments.

What parasites affect chickens?

The RSPCA names three worm types (gapeworms, tapeworms, roundworms — a serious infection can be fatal), lice (found beneath feathers, often suffocated by dust bathing), and red mites (more common in summer, found under wings or in the coop itself, harder to spot than lice).

What is feather pecking and why does it happen?

Feather pecking is when hens peck and pull at other hens' feathers, typically around the back and vent, and the RSPCA names several causes: environmental factors, nutritional deficiencies, poor health, pecking-order stress, and sudden changes to the flock or its surroundings.

What are signs a chicken needs a vet?

The RSPCA lists hunched posture, erect feathers, head tucked under the wing, hiding, dirty feathers, lameness, runny droppings, and discharge from the eyes or nostrils as signs that warrant veterinary consultation.