Here are some other symptoms of canker as expalined in an article by Colin Walker...
Depending on what stresses the birds are under, trichomonad levels will rise and fall. When high, they have a typical parasitic effect, weakening the bird, in the process creating a vulnerability to secondary infection (particularly respiratory infection) and compromising race performance. They also produce a toxin that makes the birds feel unwell. Birds with elevated trichomonad levels are said to have 'wet canker'. Signs of infection can be subtle and quite varied. Typical signs that would alert the fancier to its possible presence include:
1. 'Penguin' posture - Associated with proventricular (glandular stomach) and crop pain. Birds will lean back on their tails and gulp. Noticed particularly after eating and drinking.
2. 'Dry feather' - Due to lack of down feather drop and bloom production.
3. 'Leady' feel - Affected birds will not come into condition and feel heavy in the hand.
4. Wet dropping - Inflammation in the digestive tract creates a thirst, leading to elevated water intake and urine production. This produces a clear watery rim around the dropping.
5. Green droppings - Due to digestive tract irritation and in some birds decreased food intake.
6. Inflammation in the throat - Tonsillitis and increased clear to grey bubbly mucus.
7. Interference with crop function - Delayed crop emptying and sometimes vomiting.
8. Increased food consumption by team as a whole
9. Dry yellow canker - In birds of any age, this tells you that many other birds have elevated trichomonad levels, which have not yet passed the threshold for yellow material to form.
10. Indirect signs - Poor loft flying, poor tossing, respiratory problems that respond poorly to medication or quickly relapse, a dramatic improvement in the birds' general vigour in response to anticanker medication are all suggestive.
Definitive diagnosis, however, depends on microscopic examination of a crop flush. Microscopic changes that are suggestive of the problem also develop in the dropping,. These changes are associated with the stress of the disease and include elevated E. coli and yeast levels. These changes, however, do not occur in all birds.