I have an Ameracana with a combmb that is showing these white crusty small 'nodules' last year. I tried soaking them and picking them off thinking they were dirt, food, etc. They seemed to be attached to the comb. They looked almost like calcium deposits. I cleaned and neosporined them and put her back with the rest of the flock. She quit laying her lovely green eggs last year as well. She is is 2 1/2 Healthy otherwise. The little nodules never went away, but all else is fine. I have a White Sultan born this Feb. and she has these little concretions as well in her comb. I have cleaned them, tried to pluck them off etc. She is laying fine. Helathy otherwise I have a Cochin that is SUPER prone to vent gleet time and time again. She has not left me an egg in a year as well. she is 2 1/2 Healthy otherwise. Could I be having a fungus issue? I treat the vent gleet with typical womens yeast infection medication for 3 days in her vent and it seems to clear up. Girls are houses in a nice dry super clean coop. cleaned daily.outside run is huge, lots of grass, dirt, etc. Does get wet at times. Dust bath is wet at times. I will get photos tonight.