I was just getting ready to post the same thing I did look it up and this is what I found on it
Frounce (or Avian Trichomoniasis)
Frounce is a highly contagious yeast infection of the digestive tract. Frounce is caused by a protozoan called Trichomonas which is frequently present in the crops of pigeons. For this reason, pigeon heads and crops are generally not fed to raptors. The typical signs of frounce are white spots in the mouth or crop, often described as "cheesy" or "white plaques." These alone are not enough to diagnose frounce as plaques could be candidiosis, capillaria, or even Vitamin A deficiency, but it is one hallmark of the disease. Other signs are head flicking, difficulty breathing, or even regurgitation of food. There is a particular smell to frounce. Green mutes may also appear. A bird may suddenly appear to be in yarak, even without other changes. A swab and wet prep on a slide will show protozoans.
Flagyl, Spartrix, Metronidazole, Entramin, Emtryl (encourages the lesions to drop off), or Carnidazole (or, less preferred, Enheptin) are typically prescribed for this. One common treatment now is to treat the bird with 25 - 50 mg/Kg of Metronidazole twice a day for 7 - 10 days and swab the frounce areas with a dilute Betadine or Nolvasan solution to try to remove some of the plaques. A single 250 mg tablet can be dissolved in 10 cc water. A 600 g bird can then be given 1 cc per day of this mixture. Another approach is to, basically, address the infection with a single dosage of 125 mg per kg of bird weight. The infection plaques will die and expose raw skin that will need to be protected from any other infection. Plaques in the throat may necessitate smaller bites or food more easily swallowed.
Birds who are untreated usually succumb to Frounce within 7 - 10 days. Great Horned Owls and Barred Owls appear to be very susceptible to this. Peregrines are thought to be less susceptible to this, so a Peregrine showing frounce symptoms should also be investigated for diseases which may give similar symptoms such as Capillaria.