One of my hens has been coughing and appears to have a swelling on the -back- center of her neck. A 2nd hen also seems to have developed a swelling on the center back of her neck also but has no cough. Any idea what this combination of symptoms could be? They free range and are very flighty, so I cant get near them. They haven't been wormed in a year and its been wet, warm and humid. Ive never had a sick bird before; should I just start out trying Safeguard? The puffed section of feather on the center back of neck has me stumped. Tractor supply is my closet store with poultry meds.