1) Chlamydia in Pigeons by Racing Pigeon Laboratory Testing

Chlamydia is a microorganism that is found within the system of many pigeons all the time. There are many strains, which vary tremendously in their capacity to cause disease. Lofts tend to have resident strains to which those birds, often through their on-going exposure, have developed an immunity. Donal Barry

In such lofts, it is only when the birds are stressed that the Chlamydia can flare up and cause disease. It is through contact with other birds (strays, in race units, new introductions) that new and potentially nastier strains gain entry to the loft. Control of Chlamydia is, therefore, double-barrelled and involves the control of stress to avoid resident Chlamydia strains flaring up together with the correct use of medication and the prevention of new chlamydial strains entering the loft. Pigeon Vet 

Images of Racing Pigeons with Chlamydial:

Young racing pigeons with Chlamydial conjunctivitis where the eye has become swollen, and a tear wetness has developed around the eye along with staining of the cere.

As this is a very contagious disease it is highly recommended to flock treat as racing pigeons will not preform. Pigeons Veterinary