Bird Vet Melbourne

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Chicken Vet – respiratory disease in chickens  (CRD)

By Dr Philip Sacks


“Mycoplasma” is a bacteria and a major cause of Chronic Respiratory Disease (CRD) in poultry. The most common symptoms of CRD seen during  "chicken vet" visits are head shaking, clear weeping eyes and swelling around the head and sinuses. In more advanced cases of C.R.D poultry vets see open mouth breathing, gurgling and a smelly pus build up in the oral cavity and eyes.  We also see open mouth gasping, and open mouth breathing, at the chicken vets in Melbourne.

CRD is one of the most common causes of disease in backyard hens seen by chicken vets at Bird Vet Melbourne

Mycoplasma gallisepticum is the  infectious and can spreads  through a flock. M. ; Gallisepticum can reside in a flock until birds are stressed resulting in poor immunity and birds get CRD disease.

Signs of CRD - Chicken Vet Melbourne

The signs of CRD are weepy eyes, head shaking, gurgling.

Other diseases that have similar clinical signs are Infectious Coryza, Infectious bronchitis, Infectious laryngotracheitis and Fowl cholera.

Treatments of CRD used at Chicken Vet Melbourne

The Poultry vets will prescribe antibiotics that can help to control the disease. Most chicken antibiotics are not registered for egg laying hens – and are used off label!

Firstly Antibiotics -  Pet Chicken vet

  1. Doxycycline – is a great antibiotic against Mycoplasma.
  2. Tylosin can also be used alone but is usually use it with Doxycycline.
  3. Lincomycin combined with Spectinomycin, is water antibiotic works well and has no withholding period for egg layers – a bonus.
  4. Chortetracycline – works okay not as good as Doxycycline but has no withholding period for egg layers – a bonus.
  5. Enrofloxacin - is a great antibiotic against Mycoplasma, and other secondary bacteria.
  6. Amoxicillin and Clavulonic acid is often used in conjunction to treat secondary bacterial infections.
  7. The poultry vets also use antibiotic eye drops and Antibiotic nose drops. This route of medication is brilliant as the drugs get right to the place of infection.

Secondly – Chicken vet – Nursing Care

A very important part of the therapy is reducing stress in the flock. Often discouraging egg production, improving diet, good aeration, added warmth, reducing aggression – separating out the sick birds and reducing stress. Housing that is difficult to clean that accumulates manure, dust and vermin is not ideal.

Thirdly – in advanced cases – with pus in the Sinus and choanal slit.

These sick chickens need the sinuses repeated flushed, with sterile fluids and cleaned. Sometimes the “abscess” may need to be cleaned and material removed under general anesthesia. Advanced case need relatively expensive, ongoing veterinary therapy – Usually with good results after about 5 days in a chicken vet hospital. The birds go home on medications and therapy for the owners to continue doing – usually for a further 2 -3 weeks.

Fourthly treat concurrent parasitic disease - Poultry vets

May be recomended to perform a fecal wet preparation, crop wash and fecal flotation to check for concurrent parasitic disease, in particular parasitism. External parasites , worms and coccidial infections become more significant in sick birds. Occasionally flagellate infections are also seen. 

Prevention -  Vaccination and treating and quarantine of new birds

Chicken veterinarians  find that respiratory infections can be divided into two groups, those caused by bacteria or viruses. 

Viral diseases recognized by poultry vets causing CRD symptoms are Infectious Laryngotracheitis, Infectious Bronchitis, Newcastle Disease and Avian Influenza.

Poultry vets see bacteria causing respiratory disease: Haemophilus , Pasteurella and other secondary bacteria that invade infected sinuses.

It has been suggested that t Chronic Respiratory Disease or CRD is due to a combination of Chlamydia, Mycoplasma and E. coli. 

Chicken Vet Melbourne

open mouth breathing | chicken vet

Note the plugs in the nostrils of the Chicken , with open mouth breathing and chicken respiratory disease

chicken open mouth breathing

Note the plugs removed from the nostils in this CHook, at the Melbourne Chicken Vet.  THe chicken was open mouth breathing.

open mouth breathing chicken | chicken vet

After flushing the sinus in this chicken with sinus disease at the Chicken vet.

open mouth breathing