Just like you and me, hens get colds that cause sneezing, a runny nose and even coughing. To clear the cold in just a few days, pop a few drops if Citricidal into the drinking water. Citricidal is a natural anti-viral, anti-bacterial, anti-parasitic and anti-fungal derived from grapefruit seeds. It is a potent medicine so use sparingly. Two drops per pint or 5 drops per litre should be more than enough. It's important that hens have space to perch and that you do not keep too few hens in a large coop. Chickens perch together at night to keep warm and this well help prevent illness. Other disease prevention includes a well balanced diet that is kept clean and dry,plenty of clean water and a clean chicken coop. Be sure to keep a close eye on your chicken over the next few days. Hopefully, symptoms will diminish. If, however, your chicken develops diarrhoea, rattling and/or gasping, seek a vet's diagnosis. Your chicken may have Mycoplasma. Mycoplasma is common in poultry and is easily treated with antibiotics such as colloidal silver. Colloidal silver can also be put in the drinking water or sprayed directly into the chicken's mouth. It’s important to check that your local vet will see chickens before a problem arises. Many city vets will not see chickens. Look for a vet that specializes in birds as chickens share a lot of diseases with other birds. Diagnosing or narrowing down your chicken’s illness will help your vet enormously. Purchasing a book like ‘The Chicken Health Handbook' by Gail Damerow may prove an invaluable investment.
I read that avian flu (if that's what she's got) can be cured with 'Star Anise' a spice you can get from any supermarket and also sauerkraut. These don't have to be used in conjunction with each other, but I put them both out for my chicken who was sneezing and looking 'a bit down' and now she's not sneezing and looking very happy again
Sneezing and running nose are the symptoms of avian cold. You should show your chicken to an Avian expert/doctor for medication. Prevention is also a good option. Keep the chicken away from the dust.