One of our 7 African goslings (about 7 weeks old), has developed some pale marks on his bill, one is a long vertical line running most of the length of his bill, plus a couple of other splotches. These appeared maybe 7-10 days ago. The siblings show no such marks. All 7 are behaving normally. Kind of wondered if this is some kind of goose bruising? Any insight would be appreciated. Thanks!