NOT Mycoplasma!

The vet just called with very interesting lab results. They go to show that it can look like a duck, quack like a duck and walk like a duck, but not be a duck. My hens did not have Mycoplasma. They had foamy, shut eyes and respiratory distress and one died, all textbook symptoms of Mycoplasma – but they had a different infection. Despite $137 worth of lab tests, we’re still not sure what they did have, but we know what they didn’t. The tests were conclusively negative for Mycoplasma. There was a slightly elevated level of E. coli and gram-negative bacteria. Perhaps one of those, or both, caused the symptoms. Perhaps not. Fortunately, regardless of the cause, the treatment worked.

I’m of two minds about how worthwhile those tests were. Obviously, since I’m just getting the results back now, the knowledge they provide isn’t timely. If I’d waited to make treatment decisions based on the tests more hens would have died. However, if the Tylan and doxycycline weren’t effective, it would have been important to confirm exactly what infectious agent we were fighting and the cultures would have been worth the expense. In the end, for me, it’s worth it to find out what I didn’t know. I’ve a responsibility to you, my readers, to get it right. So much of what we think is going on with our flocks’ health is pure conjecture. In this case I’m pleased to know a tad more than I did before.


  1. Interesting to hear those lab results. I had two separate incidents with two chickens. One was a young pullet, the other an older hen…and this happened months apart. Each seemed tired, sitting still while the other hens were normal. Then there was a “searching for air” movement of the head, beak wide open and gasping. NO pasty eyes, poop normal, eating okay but not really interested, and no runny nares or comb discolor. The pullet died after a day, the older hen died after a few hours. The only thing I could find in the disease book any way similar to those symptoms was some form of low impact Newcastle. No other hens were affected after many weeks now. I saw no sign of internal parasites. This seems different than mycroplasma, too. Hmm. Puzzlement.

    • There are MANY diseases not in the poultry books. Most of the people writing the books are repeating other books and few of the experts have done to do lab tests to back up their assumptions. Your hens (and mine) could have had viral infections. The antibiotics attack deadly secondary infections. My best guess though is that your hen had internal issues, not respiratory failure due to infection. That’s why necropsies are so important for fact finding – but not necessarily something a backyard hen keeper needs to do to manage a flock.

  2. I have ZERO experience with birds, but find that doxycycline is frequently my drug of choice when waiting for test results on some illnesses in dogs and cats.

  3. I find it very frustrating that there is limited information on chicken diseases. I have had numerous necropsies done but they did not find evidence of any of the common ailments. Perhaps we need someone with big bucks to fund more research in this area since backyard chickens are so popular. And teach more veterinarians to take care of our chicken pets!

    • Shelley- you’ve had necropsies done? By the state lab? Private lab? Interested in why you had them done and what you found. Email me privately if preferred. Agreed that there’s very little that is known about backyard hens. All of the necropsy advice/instructions I’ve found are for young commercial birds. There is a vet in England that is specializing in pet chickens. I follow their blog and tweets, but am not convinced they’ve found much real research to back up what they recommend.

  4. You managed to nurse two hens back from near-death and save the rest of your girls on an educated guess. Sorry the lab results weren’t more conclusive, as they might

    Being a future hen keeper, I went to a ‘Backyard Hen Keeping’ lecture at the Los Angeles Arboretum last Saturday. Specific mention was made about wild birds bringing problems. I thought about your experiences these past couple of weeks in relationship to how careful you are with cleanliness. Even then they get sick. Is there no way to prevent this?

    BTW, the speaker has a 9-year old Marans who just stopped laying last year! Amazing. I’m thinking maybe longevity has to do with climate? You mentioned the Mycoplasma can’t survive in the sun. Any thoughts?

  5. Oops… first paragraph: … as they might have given you some help in the future.

  6. just dashing out to farmer’s market in Rye (land of buckets) but could it have been infectious coryza? What does it say in Victoria Roberts book about that? Will check later.

  7. Have just checked VR and Wendy may be right (although the lab should have picked it up?)
    “Infectious Coryza or Haemophilus paragallinarum
    Not present in the UK. Signs: conjunctivitis, nasal discharge, facial and wattle swelling. Vaccine available.”

    I’m as surprised as you were about it not being Mycoplasma. But I was also shocked how quickly your birds went down with it. My only experience of Mycoplasma was a ‘slow-burn’ condition which worsened in cold winter weather.

    I’m pleased your birds seem to have got through the worse. And you’re right about vets knowledge being based on farm studies where flocks are large and birds are culled at 2 years max. Expert knowledge of back yard flocks is very rare.

    Best wishes

  8. The lab tested for every single possible infective agent – over 40. Sometimes you can’t put a name on a disease. I think that the poultry health books are limited and try to pigeon-hole all respiratory aliments into the known slots. I think that if everyone had their birds tested, we’d find that there’s a much wider range than “mycoplasma” or “infectious coryza.” But, since the treatment is the same, and the expense is great, I wouldn’t suggest testing – except in situations where the drugs aren’t working. OTOH, I’m relieved to know that my hens aren’t carriers of mycoplasma, and that the bacterial infection was fleeting. For us, here, it was money well spent.