I work at a feed store, and yesterday I received a shipment of 50 ducklings. When I put them into their temporary home I noticed one of them had a small brown smudge on his head. I thought it was just a lil ducky poo from shipment, but when my co-worker went to wipe him off, she noticed there was actually a little hole there. We separated him for his safety, and put one of the smallest runts in with him so he wouldn't get too lonely. I put "PoultryAid" on the spot and he seems to be doing ok. But it still looks pretty bad. Is there anything else I should do for him? Any ideas what it is? Is it a worm? I looked through some books and couldn't really find anything that matched up with this lil guy. Thanks in advance to anyone with ides for me!