Mycoplasma Gallisepticum

Many backyard flocks these days are carrying Mycoplasma. There are many different kinds of Mycoplasma but Mycoplasma Gallisepticum (M.G) is the most common.

Mycoplasma Gallisepticum causes respiratory disease and can weaken the birds immune system sufficiently for them to pick up any disease that they come into contact with. Small bubbles in the corners of eyes and swollen sinuses are usually the first sign of Mycoplasma.

Once birds have been infected, they become carriers and remain infectious for life. Some birds seem to have a good resistance to M.G. and out of an infected flock, a few may die, others may become ill and recover and some may not show any symptoms at all. The first time they are ill seems to be the worst and subsequent outbreaks seem to be milder.

Bringing new, perfectly healthy younger birds into an established flock of carriers is typically a problem. New birds can be Myco free but with the stress of being moved and not having much resistance to M.G. will become sick after a week or two of arriving and the established flock appears to be healthy.

The stress trigger can be small such as moving birds to different housing, adding new birds, a change in diet, parasite infection or even a sudden change in the weather (snow for example).

Some birds die, some birds are only carriers and some birds are sick and recover but repeatedly have bouts of illness (not normally as bad as the first time though). As it can be carried by wild birds, it is a problem with birds that are allowed to free range as they can come into contact with it easily. The infectious agent survives for only a matter of days outside of the birds. Commercial operations operate an ‘all in, all out’ system to ensure they do not have problems.

A blood test can be done at your vets. The blood samples are usually sent to a specialist poultry laboratory for analysis. In Ireland, it is advisable to test all new stock that you buy since it is a notifiable class A disease and the Department of Agriculture in Ireland recommend culling all birds that test positive.

Other Names: M.G, Chronic Respiratory Disease, CRD, Roup (in older poultry books), Stress Disease, Infectious Sinusitis (in Turkeys)

Symptoms: In growers: Loss of appetite, slow growth, In Chickens & Turkeys: Ruffled feathers, fluid in eyes (small bubbles in the corners of eyes), coughing, sneezing, ‘darth vader’ breathing, gurgling / rattling, swollen face, strained crow in cockerels, drop in laying in hens, sometimes loss of appetite, sweet smelling breath.

Chicken with Mycoplasma

Chicken with Mycoplasma Gallisepticum showing difficulty breathing and small bubbles in the corner of the eye. Photo courtesy Grant Brereton.

Area affected: Respiratory system (mainly) but can effect the Kidneys.

Causes: Mycoplasma Gallisepticum Bacteria.

Transmission: Infection from other carrier birds (from their respiratory dischages), including wild birds. Through hatching eggs. From infected dust / bedding material. Chickens and Turkeys can cross infect one another, other species have their own type of Mycoplasma that cannot cross infect. Mycoplasma is highly contagious and can be carried in on shoes, clothing and feeders / drinkers etc. Mycoplasma can survive for several hours on these things.

Diagnosis: Contact with wild birds or other carriers (poultry shows), bringing new birds in that are carriers, stress factors (change of food, house, worming, over crowding, new birds in the flock, cold weather – snow covering the ground for example, shortage of food or water, ammonia from soiled bedding). Breathing difficulty, laboratory identification of bacteria in post mortem, identification by blood test.

Prevention: Good biosecurity, minimise stress, vaccination is possible but is done via an inhaled mist and equipment to administer is expensive, keep birds immune systems strong with the right diet. Fresh crushed garlic in food or water is great for the immune system and Apple Cider Vinegar. After an infection, disinfect housing and leave for 2 weeks. Mycoplasmas cannot survive for long in the environment.

Treatment: Antibiotics from your vet: TylanBaytril, or Gallimycin are often prescribed. Treatment needs to be early on for a greater chance of recovery.

Risk to Human Health: None known.

Many respiratory problems are labelled as “Mycoplasma” by backyard chicken keepers but there are other respiratory diseases. You can read more about respiratory problems in chickens here.

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Tim Daniels

Tim is the founder of the poultrykeeper website and lives in Herefordshire, UK. He keeps Cream Legbar chickens, Silver Sebright bantams and hybrid layers for eggs, Abacot Ranger ducks, Brecon Buff geese and some quail.

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  1. I believe they will always be carriers Sarah, however the chances are the others are also carriers already, it spreads like wild fire… You can get a blood test done, or take your chances I guess.

  2. Hi! My Bourbon Red hen just recently came down with a swollen head and nasty looking eyes. We are trying to figure out what this is and if it will effect the rest of our flock. MG seems like it might be the culprit but I would like a more definite answer. Thanks so much for your time!

    • Hi Miranda,
      Those symptoms certainly sound like Mycoplasma Gallisepticum and turkeys do seem to suffer with it just as much as chickens.

      I can’t be definitive, only a vet would be able to take a blood test and examine the hen to confirm this disease. Yes, it can spread to the others, or they could already be carrying it but either way, I would isolate the sick bird and then visit the vet to see if they have a recommended course of antibiotics.

  3. It’s always difficult to diagnose diseases without examining the bird. It sounds serious enough for a trip to the vet so I would let them try to diagnose.

    Fowl Pox springs to mind (which is very painful for the bird) but there are many diseases that can show some of these symptoms.

    • Tim thanks….yeah we thought it was pox too, but it’s going on two months! From all I have been told, pox clears up in less time. It seemed like it cleared up, then a new attack started with lesions that looked like fever blisters, then to the pasty looking stuff. That chicken is still eating away and pretty perky. I am prepared for anything though.

      It’s starting to sound more like favus, that she picked up due to immune issues post pox. I am going to take a scraping to my vet tomorrow! She is shedding like crazy on her trunk, like peeling skin and with a few whitish yellow streaks. I know it’s hard to diagnose from afar, but I just need to gather some data for my vet, who is a country vet, but not much on chickens?

      • Let us know how you get on. In the UK, there are some vets who specialise in poultry and we have a list of poultry vets here on the site, but I don’t think you’re in the UK…

  4. Antibiotics are usually given – the secondary infection gives symptoms in the upper respiratory system. The eyes, and rasping breath / laboured breathing.

    Sorry we have nothing on favour – a research project of the future I guess!

  5. Sorry I don’t really have good news for you.

    There are a number of respiratory diseases so without having them diagnosed, it’s hard to know what’s wrong.

    What I’d suggest is that they are very sick though and should either be taken to a vet who can diagnose and prescribe the right treatment for them, or they should be dispatched humanely.

    It would be wise not to eat eggs after they have had antibiotics anyway (because of antibiotic resistance that can effect us) but egg laying is usually affected anyway.

    It’s really a case of buying healthy chickens or you don’t know what’s in store.

    If you do ‘start again’ then remember to disinfect the area to prevent re-infection of fresh stock.

    Again, sorry I’m not exactly helping but personally, I would dispatch these birds, clean and start again.

    • The hard part is they don’t seem sick except sneezing or a cough, I can’t tell the difference. ill see what happens this winter, thank you

  6. Hi, I was hoping someone may be able to give me some advice. We took over a property 4 years ago and inherited a goose and a gander with the pond. Two years ago we introduced a male and female duck. There are also a range of wild birds that live on the pond. Moorhens particularly and some mallards come and go. Not long after arriving my male duck started to have problems with his eyes. ( a bit like conjunctivitis) I went to the vet who gave us antibiotics and they worked for a few weeks then it came back we treated it again and it seemed to clear. It came again last year but very mild and went in a day or two but he still seemed to have a white crust at the bottom of one eye. This year my gander has developed a similar problem. I suggested it may be mycoplasma to the vet (after looking up symptoms of a bubbling eye) and they are prescribing Tylan. We had about 20 days worth and that seemed to do the trick but then a feed days later it’s back again. He’s also started to pull out his feathers, Is constantly itching his eyes, And seems to have leeches living in his beak? When the infection goes so do the leeches? I’m not sure if they are part of the problem or if he’s trying to clean himself? so I put a bucket of fresh water out for him to wash in and he seems to shake them off in there? We lost our female goose suddenly about a week before his symptoms appeared she just died overnight with no symptoms she was only 5 years old. No sign of illness but now I think the two may be related? Any advice appreciated I’ve grown very fond of this fella and want to help him get better – thanks

    • I don’t recognise these symptoms but have you tried worming them?
      I’m also wondering if there is something in the pond – does it have fresh water flowing in or is it stagnant?
      Myco from my experience seems to hit Turkeys and Chickens.