Symptom Reference Table (Free)
Over 90 different symptoms and their associated diseases and ailments in a handy PDF format you can print.
This page will cover some of the most fundamental aspects of pigeon health including common diseases and their associated symptoms, preventive measures in and around the loft, and vaccination basics.
Here are a few of the most easy to spot signs that a pigeon may be unwell.
'Going light' is commonly used to describe progressive weight loss in pigeons
Essentially, the bird continues to lose weight, in some instances they will retain fairly tight feathers and white wattles giving the outward appearance of good health. In other cases the bird will ‘blow’ it’s feathers, and tend to huddle or hunch it's back. Also, at times the droppings will become sloppy and tinted green with bile as you’d see with diarrhoea.
Going light is a general symptom for a range of ailments and diseases but primarily coccidiosis, polyneuritis, and bacterial infections such as E. Coli.
The feathers stick out away from the body as the pigeon tries to cool its temperature resulting from fever. It lifts the feathers to allow cool air onto the skin.
Feathers of a sick pigeon are dry and coarse, appearing to be brittle to the touch, whereas a healthy pigeon has satin smooth, almost ‘greasy’ feathers.
A poor posture, i.e. hunching with shoulders up and head drooping may be an indication of bad health.
Wishy-washy, dull, and vacant eyes often accompanied by the irregular movement of the nictitating membrane, which, instead of flicking across the eye with speed, crawls across it, as if tired and without energy.
This table should serve as a general guide on symptoms and the respective possible diseases and ailments. If you notice any of the below symptoms a proper investigation into the pigeon’s health should be conducted by doing a swab and dropping test.
Air Sacs, Inflammation
Infectious Catarrh, Ornithosis, Mycoplasmosis
Oxygen deficit caused by a respiratory disease or by insufficient loft ventilation; feed mixture too high in protein.
Breath, Short of
Salmonellosis, Ornithosis, Mycoplasmosis
Crop, Mucosa, Swollen
Young Bird Sickness, Trichomoniasis
Droppings are one of the best indicators of a pigeon’s health. If you suspect a pigeon is unhealthy, whether you have observed any of the above symptoms or not, it is of paramount importance that you took a closer look at the droppings.
If you witness a sudden change in the form or colour of the droppings there is usually something wrong, especially if you haven't altered the feed or given them any kind of medication.
A good dropping is usually perfectly formed, quite small, and will have a little white cap and a down feather on it.
This is a great article on dropping interpretation.
A loft that is not well-maintained, infested with rodents, has lack of airflow, is too humid or that allows stray birds in and amongst your pigeons is a recipe for numerous health conditions.
Therefore, it is important that you take every precaution to ensure that the pigeons are living in an environment properly suited to promoting good health and well-being from a physical standpoint as well as a mental one.
Overcrowding can be severely detrimental to a pigeon's health yet it is often overlooked as fanciers prioritise building larger and larger teams year on year without first considering the capacity of their available facilities, i.e. section, boxes and perches.
Not only does overcrowding increase feather dust and can create excess moisture, but as they reach about 8 weeks old pigeons start to become territorial and compete with one another.
Therefore, each pigeon needs space to call its own, be it a perch or box, otherwise there will be non-stop fighting.
Another thing to keep in mind is that males are comparatively more competitive than hens, so it's advisable to keep fewer cocks than hens per cubic meter of loft space.
Aside from negative affects on health, an overcrowded loft may suffer more ‘flyaways’ as well as a drop in fertility rates, almost as if the pigeons can sense a lack of available resources, be it space or air.
To be in perfect health a pigeon requires “660 litres of pure oxygen” on a daily basis. 
Having more pigeons than the loft has enough fresh air to support means that some birds will be deprived of the pure oxygen they require.
You can read more about oxygen and ventilation on our loft page here.
Lack of territory, fresh air and other factors creates stress, this in turn can lead to a number of second and third-order consequences.
For example, stress robs pigeons of their appetite which in turn brings the bacteria in the intestines into a state of imbalance making the pigeon more susceptible to diseases such as E. coli.
The main vaccinations for racing pigeons include those for poxvirus, paratyphoid and paramyxovirus (PMV). Paramyxovirus vaccinations are mandatory in many countries, including the UK, Netherlands and Belgium, pigeons without a PMV vaccination certificate are unable to complete.
Pigeons should be vaccinated against pox when they are 5 weeks old then once every year at least 3 weeks before the start of the racing season. 
Contrary to popular belief, vaccinating a pigeon once for pox does not mean lifelong immunity, however, pigeons that have come into contact with the virus ‘naturally’, as it were, are unlikely to get it again.
There are a number of vaccines on the market that vaccinate against both pox and paramyxovirus. But while these can save time and money, they are not necessarily as effective as regular vaccines.
Vaccinations for paramyxovirus should only be given once the pigeons are at least 3 weeks old, and then again yearly at least 3 weeks before breeding. The best time to vaccinate young birds is when they are between 6 and 8 weeks old. 
According to veterinarians, it is unnecessary to vaccinate pigeons for paramyxo that are not being raced on a yearly basis, instead, you may vaccinate once in the year of birth and then again as a yearling.
Vaccinating for salmonella to guard against paratyphoid infection should be done after the pigeons are 5 weeks old then twice again with 2-week intervals, then 3 to 4 weeks before breeding. 
Before vaccinating against salmonella it is important to first verify that no salmonella infection exists in the loft by having a laboratory test conducted.
Adverse reactions and even death can occur if pigeons that already have salmonella are vaccinated. Vaccinating with an auto vaccine made from a culture from your own pigeons is recommended following a treatment with Parastop, Baytril or Trimetroprim.
First and foremost, medication should generally only be given if the bird(s) have been diagnosed and you know what you are treating for.
Trichomoniasis (Canker), of course, is the exception to this rule and generally needs to be kept under control at all times through the use of “preventive” medications. 
While it’s not generally advised by avian veterinarians , it’s worth noting that some fanciers also insist on including Coccidiosis in their prevention-through-medication activities.