Hi! I got my husband two mallards from tractor supply for valentines. Not sure if the age an both are eating an chirping away, but I noticed crustys on them today. One it's starting to show around the back of the feathers by the eye an neck an the other had it in between its wings. I washed (gently) them off but was still wondering as to some guidance. Bedding is changed ruglarly an water to. Read about a chamomile wash an may try that. Thank you.