A-Z of chicken diseases

[OrpingtonManiac]

What exactly is anaerobic spirochaete brachyspira? Is it a type of bacteria?

Yes, they are. They are classified as bacteria and are found in the order spirochetales.

 

[OrpingtonManiac]

23. Avian leukosis
This refers to several leukaemia-like diseases caused by the avian leukosis virus (ALV). ALVs consist of 10 subgroups labelled from A to J, with 6 affecting chickens. A and B are the most common in chickens, especially egg laying hens, followed by J which occurs in broilers and egg layers. Subgroup E is oncogenic (causes tumours) and is widely present in domestic, non-commercial chickens. Hens are most commonly affected.

Lymphoid leukosis: This is the most common type of cancer caused by ALV in chickens. It occurs in chickens of 4 months or older. Tumours often develop in the liver, spleen and bursa of fabricius. Less commonly: Kidney, lung, gonad, mesentry and bone marrow. The bursa of fabricius is always involved.

Myeloid leukosis:
Caused by the subgroup j, it occurs in two, often overlapping, forms: myeloblastosis and myelocytomatosis. Myelocyomatosis causes multiple masses (myelocytomas) on the shanks, head, oral cavity, trachea and eye. They are often nodular and multiple, with a soft, friable consistency and of a cream colour. This mainly occurs in adults. The J subtype is genetically unstable.

Avian osteropetrosis

Transmission:
ALV is transmitted horizontally (from bird to bird by direct of indirect contact) or vertically (from infected hens to the offspring via their eggs). Most chicks are infected by contact with infected birds, which shed the virus in their faeces, saliva, scales and skin flakes. ALV has a short lifespan outside the bird.

Symptoms:
Loss of appetite; pale, shrivelled comb; enlarged abdomen; weakness; diarrhoea; weight loss.

 

[OrpingtonManiac]

Chicken anatomy:
Respiratory system part 1:

The chicken respiratory system begins at the head region. Parts of the respiratory system in this area include the nasal opening, nasal cavities and the pharyngeal region of the mouth. The cranial larynx (the glottis) is located in the pharyngeal region, and is the opening to the trachea. The pharyngeal region also has openings to the oesophagus. The glottis closes during eating to ensure food does not enter the trachea. The trachea is made up of cartilage rings to prevent the trachea collapsing. After the syrinx, the trachea divides into two smaller bronchi. Each bronchus enters a lung, which are small, attached to the ribs and do not expand.

 

[OrpingtonManiac]

Chicken anatomy
Respiratory system part 2:

The bronchi branch into smaller secondary bronchi and then into hundreds of smaller loops called parabronchi, which have many blood vessels. This results in a large surface area.
The rib cage does not expand as to provide a strong anchoring point for flight-enabling muscles.
The lungs also contain air sacs, which fill are large proportion of the lungs, are ballon-like structures at the end of the airway system. They act as bellows, sucking in or blowing out air to hold part of the total air volume. There are 9 main air sacs. These have very few blood vessels and do not play a major role in gas exchange, instead ventilating the lungs.

Air flows in one direction in birds lungs, due to the continuous parabronchi.

The avian skeletal system also is a part of their respiratory system; some bones are hollow. The air sacs connect to these bones. These are called pneumatic bones and include the skull. They provide a secondary route for gas exchange as well as being lighter, aiding flight.

The trachea is much longer than that in mammals, resulting in a larger amount of air to enter per breath. This results in a relatively low breathing rate.

 

[Squawkers]

You took a surprising turn with anatomy, but I love it!

 

[OrpingtonManiac]

You took a surprising turn with anatomy, but I love it!

Glad to hear it! I love everything chicken, so their anatomy interests me loads

 

[Squawkers]

Glad to hear it! I love everything chicken, so their anatomy interests me loads

I love everything chickens and I like anatomy too! I studied it quite a bit in school too.

 

[Squawkers]

It’s fascinating how similar (yet how different) human and bird anatomy is.

 

[OrpingtonManiac]

It’s fascinating how similar (yet how different) human and bird anatomy is.

I know right! I was so surprised to find out chickens bones are part of their breathing system. I dont know why, but i thought chickens and humans would be quite similar (apart from the whole egg-laying thing!) anatomically.

 

[Squawkers]

I know right! I was so surprised to find out chickens bones are part of their breathing system. I dont know why, but i thought chickens and humans would be quite similar (apart from the whole egg-laying thing!) anatomically.

Yes, that is really surprising!