Late Saturday I noticed one of our hens had some swelling on one side of her face and her eye was partially swollen closed. On Sunday morning I started all 7 chickens on Duramycin (1 t per gallon, changed every 24 hours). Also on Sunday morning I found a double soft egg under the roost that she had laid, I'm sure it was hers as only 2 hens have started laying and the other had layed one in the nesting box. The hen with the swelling had been laying regularly prior to Sunday but hasn't since I found the double soft egg. This morning her eye is completely swollen shut, no improvement since starting the Duramycin. None of the others are showing any symptoms. She acts normal other than the swelling and it's only on one side. She's eating and walking around, you wouldn't notice anything wrong except for the obvious swelling. I don't see any discharge, she doesn't seem to be in any respiratory distress, it's just the swelling on one side of the face and it happened pretty rapidly. The swollen area is not soft and "squishy", feeling it it feels hard. It didn't get really cold until after she was showing symptoms and the coop does have some heat so it shouldn't be frostbite. Any ideas what could be causing this and if I should use another course of action? I do have some Tylan soluble coming today, should I switch medication, or try something else? Here's a couple of pics: Thanks for any help on this!