What is coccidiosis, or "cocci"?
Dangerous in chicks, present but rarely fatal in adults.
This is a really, really common illness of chicks up to about the age of 12 weeks.
It’s pronounced “cok-si-di-O-sis”, or “cok-si”.
The Internet is full of information about cocci; this is a very plain, somewhat simplified version of the information out there.
Summary
Cocci is a sort of parasite that eats the rich lining of the gut. It's not bacteria or a virus.
Present everywhere, but particularly dangerous for chicks under the age of 12 weeks.
Very rarely affects adults.
Early symptoms are slowness, sleepiness, and a hunched appearance.
A messy bum and skinniness may appear next.
The classic bloody droppings appear much later. Don't wait for blood before you treat.
Spread via ingestion of infected droppings in warm, damp, crowded conditions. Prevent by preventing those conditions.
Treat with Baycox or Amprolium from preference. Is not treated with, or impacted by, broad-spectrum antibiotics, antimicrobials, antiseptic, or any treatments that claim to have these properties.
If not treated in chicks, is generally fatal. Highly contagious; it’s possible to lose every chick in a hatch if it’s not managed.
If treated too late, chicks can recover but may suffer lifelong lack of thriftiness due to the damage.
Overview
Coccidiosis is caused by a sort of parasite (Latin name: Eimeria). It's found in all soils. The lifecycle of it is similar to worms, where the eggs are excreted via droppings, scratched around and then re-ingested by the chicks eating or drinking feed contaminated with the infected droppings.
The eggs - called "oocysts" in this context - hatch in the gut, and feed off the protein-rich walls of the gut.
Adult chooks generally regrow the walls really fast, so coccidiosis doesn't cause issues.
Chicks, however, are very small and still developing, so the loss of their gut wall means they can't absorb food effectively. Too many cocci oocysts overwhelm them, and they start suffering a cocci "attack".
Symptoms
The first symptoms are lethargy and slowness. They just seem to fall asleep too easily, and they start developing a hunched, dropped-wing look. This is caused by the slow starvation they're starting to suffer. It is not because they’re cold, or loners, or wanting time to themselves. Chicks hang around in groups, and they like it that way.
As the cocci develops, they get very thin, pale, and “beaky” around the face. They will probably have a messy bum, and some people may suggest they’ve got “pasty butt” or worms. “Pasty butt” is possible, but worms at that young age is very unlikely.
Later symptoms are blood in the droppings, as the parasite eats too much. This is often considered the main cocci symptom, and people will often say “but there’s no blood in their poo!” when discussing why their chicks seem a bit “off”.
This is actually quite a late stage of the illness and unless treated immediately, the chicks will die.
Note that cold chicks can look like chicks with cocci. Never let chicks get cold; this can kill them even fast than cocci, and it can certainly make the risk of getting sick from cocci much higher.
Cocci spreads incredibly fast in groups, via the infected droppings. If one chick looks sick, you can be sure the others are suffering as well, but not yet showing symptoms.
But I’m using medicated feed!
Most chick feed is medicated with something that kills some, but not all, of the cocci oocysts. Chicks need exposure to SOME oocysts to get used to their presence, otherwise they'll get a nasty shock when they go into the main flock and are exposed to the full force of the Eimeria population there.
An attack can occur even despite the medicated feed, however, so you sometimes need a medication to kill all the oocysts. Amprolium and Baycox are the best medications for this.
Treatment
Treating at the lethargic stage should see a 100% recovery with no deaths or long-term impacts.
Treating at later stages, or after deaths have occurred, may see further deaths, and some that recover may always be a little less healthy - unthrifty - than other adults of the same age.
A cocci attack can also open chicks up to other illnesses that they might otherwise shake off; for example, respiratory illness.
A commercial coccidiosis medication is required. Treat as soon as you see any slowness or lethargy. Chicks do not stand apart or fall asleep on their own; they run around, eat, and drink in groups. Chicks that stand out due to slowness or sleepiness are most likely showing early cocci symptoms.
In order of quality and price:
Baycox. Very, very effective. Very, very expensive. May only be available online in large quantities (for example, one litre bottles) or through vets. Can be used as a preventative and treatment of an active “attack”. Is the only really effective treatment once blood in the droppings is seen or deaths have already occurred.
Amprolium. Present in the readily-available Coccivet and Cocciprol medications, among others, and can also be bought under the name Amprolium. Available online and through vets, may be found in some produce stores. Can be used as a preventative and treatment of an active “attack”.
Orege-stim. This is an oregano essential oil extract. It’s been shown to be effective against cocci, and is now the only permitted medication against blackhead in turkeys, which is a cocci-like illness of turkeys. Unsure how effective it is once deaths have started occurring; I haven’t tested it myself.
Everything else. Sulpha-quinn (no longer available), Sulfa-D, Keystat, and a few others. Effective if treated early, or used as a preventative. May not be effective in an active attack.
Treat according to the dosage on the container.
How often do I treat?
You should treat once (as per the instructions on the medication - it’s generally a 3-5 day treatment) and then use preventative actions to stop it happening again.
Repeated cocci attacks will significantly weaken chicks. It indicates something’s not quite right - either with the chicks, or with your setup. We’ve all been there, and it’s heart-breaking and frustrating to try and deal with it.
Repeated attacks can occur if weather conditions are hot and humid. Try to implement preventative measures as quickly as possible, aimed at reducing how often chicks can accidentally or deliberately eat their own droppings.
Use Baycox if you have to treat repeatedly, and be aware that repeated attacks come with a significantly increased risk of death or long-term unthriftiness.
Where to buy treatments in Australia
Petshops like Petbarn, Pet Stock, Pet Circle, Vet n Pet Direct. Including online. Most likely to have:
Amprolium (under that name, or names such as Coccivet or Cocciprol)
Sulfa-based drugs like Keystat or Sulfa-D
Rural produce stores. Most likely to have:
Amprolium (under that name, or names such as Coccivet or Cocciprol)
Sulfa-based drugs like Keystat or Sulfa-D
Online. Best places to find:
Amprolium (under that name, or names such as Coccivet or Cocciprol)
Sulfa-based drugs like Keystat or Sulfa-D
Toltrazuril (Baycox)
Orege-stim
Online places include:
Allfarm (Amprolium and Toltrazuril)
Aussie Chook Supplies (Orege-stim, Amprolium)
Gecko Dan (Cocciprol, Toltrazuril -Baycox)
Vet Products Direct (Amprolium, Baycox)
How to prevent
Eimeria likes warm, wet conditions. It loves brooders, and the conditions that occur about 3-4 days after major rain or thunderstorms.
As it’s excreted in droppings, it spreads particularly fast where wet droppings can be trodden, spread, and eaten quickly.
Therefore, cocci can be significantly prevented by providing lots of space, keeping chick-raising conditions clean and dry, and hanging feeders and waterers up where droppings can’t be flicked into them. Change food and water regularly to ensure it’s not contaminated.
People have had success keeping chicks off the ground until their digestive systems are a bit more mature at 8-10 weeks of age. Cocci oocysts live in the soil where chooks have been, and are particularly active when the droppings are still damp.
I use a large pen on a deep concrete verandah, which works very well. Raised cages, or pens on concrete which can be easily hosed off, can help a lot.
If you do this, however, make the introduction to the soil very gradual, or you risk their systems being overwhelmed all at once.
Space helps a LOT. Give chicks as much physical space as humanly possible. If you have chicks under a broody, make their separated area as large as you can. The idea is that the droppings are completely dry and crumble into the soil before the chicks come back to that section, which makes it less likely they’ll eat fresh cocci oocysts.
I saw a major improvement in cocci management when I had hens with chicks ranging around a pen about 20m x 6m. Yes, THAT much space.
Use feed medicated with a mild dose of anti-cocci medication, or unmedicated feed with a preventative dose of cocci medication (Amprolium or Baycox) in the water.
Understand your local weather conditions. Cocci “attacks” seem to occur about 3-4 days after a major rainfall; many of us pre-emptively treat on about day 2 to prevent this.
Does it cause long-term problems?
If it’s treated at the slowness and lethargy stage, no. You’ll have to gradually build up their resistance to the oocysts again, however, so take it slowly. But chicks should make a full recovery.
If you’re treating chicks with bloody droppings, and if chicks have already died, any chicks that survive may have long-term lack of thriftiness as adults. It depends how bad the damage was before the treatment started.
“Unthrifty” means “always a little bit unwell”. It means that adults might be more susceptible to any illness going around, may be prone to getting sick where everyone else is fine, may not lay many eggs in a lifetime, may not put on weight well, may suffer badly during the annual moult.
I had terrible problems with cocci early in my poultry life. In one attack, I lost 3 out of six chicks. Of the three that survived, two had long, happy lives, while the third was always a bit sickly and under the weather. She only laid three eggs in her entire life, and was always a bit hunched and ruffled. Knowing what I do now, I suspect she was constantly in a little bit of pain. She died at two years of age from a respiratory illness during winter.
Can it affect adult chooks?
Coccidiosis can affect chickens of all ages, although chicks are the most vulnerable as they haven't developed a resistance.
In theory, adults should be resistant to the particular strain of Eimeria spp. on your property, and any cocci-like symptoms are probably attributable to anything else. Adults most at risk are those whose health is already compromised - illness, poor diet, stress or previous coccidiosis attacks, which may have caused a failure to thrive.
However, ongoing unpleasant weather conditions - for example, the ongoing wet along the eastern states in Australia - could definitely trigger vulnerabilities where you wouldn’t expect to see them.
It's debatable as to how many deaths in otherwise-healthy birds it could cause.
There are also multiple strains of Eimeria, and new ones could be introduced by wild birds from another location.
Combine any of the above with damp, cold, and/or cramped living conditions, and adults can be overwhelmed by a coccidiosis challenge. Vets do sometimes diagnose coccidiosis in adult hens, but whether this is because it's the cause of an illness, or because they've found cocci oocysts in the gut when trying to diagnose one of those annoying vaguely unwell chooks, is hard to say.
If an adult hen is being affected by something else - botulism, or E. coli, or salmonella, or respiratory illness, for eg - then yes, cocci could be a contributing factor to its death. Noting that all these other illnesses of cold/wet/exposed situations ALSO cause death, and tend to have very vague symptoms.
Does it affect other animals?
Yes.
In turkeys, it’s called “blackhead”, and can only be treated using the oregano-based medication; the Amprolium and other medications were withdrawn from use for turkeys a few years ago.
In ducks, it’s still coccidiosis. We don’t see much reference to it, and even Merck’s Vet Manual doesn’t have a lot of research for it. Where it has been investigated, however, the basic principles apply - it can affect both ducklings and adults, but ducklings are more likely to show major impacts.
Symptoms are the same as in chicks - sleepiness, lethargy, and a “tucked” appearance. This PoultrySite page is a brief, but helpful, overview. Given that ducklings are, by design, raised in damp conditions, prevention might be trickier than it is in chicks, but treatment is the same where clear symptoms present - Amprolium or the sulfas.
It also affects other animals such as dogs and goats. The treatment is the same, but the particular variety of Eimeria is species-specific; chicken coccidiosis oocysts don’t affect goats or dogs.
More information
This article was originally developed for the Facebook group Australian poultry by Backyard Poultry.
Got comments, feedback, more advice, your own stories, corrections?