Tonight I realised some of my chicken have a disease.. but I don't know what it is or how to treat it. I noticed a young bird had 'funny looking eyes' and I picked it up to have a closer look. The ring of skin around its eyes is thickened and some parts look swollen and dry. Its wattles have gone hard and so have the corners of its 'mouth'. I checked other birds.. and have found another one with the same problem.. and one more showing some signs. I have separated them. The first one is the worst. .and it smells bad around its face... kind of sickly sweet putrid smell. The eyes are not watery and there is no mucus or discharge from them or the beak. The birds are breathing normally. They are all a good weight (so must be eating OK).. and they are still lively and acting normally. I have about 30 birds of mixed ages. I did add several guinea fowl keets about one month ago... but they are showing no signs of sickness. None of my adult chickens are showing signs either, only these half grown ones. So I would like to know what you all think is wrong.. and also how serious this is and what, if anything, I should do next. Thanks.