Chicken sneezing, no other symptoms

[beetandsteet]

Hi! I have a 6 year old barred rock hen. Just this morning, I noticed she is sneezing every now and again and sounds like she has mucous in her throat (not just the normal sneezing from dust). Other than this, she seems to be okay. Eating, drinking, red comb/wattles, no discharge from eyes/nose. She even laid an egg today.
She's already not very active, she has had a limp for the past few years which slows her down.
We introduced 6 pullets to our flock last week after they were in quarantine for awhile. They all appear to be healthy.
Does anyone have any ideas?

 

[Eggcessive]

I would be concerned that the new pullets could have brought something into the flock, even though they may not show symptoms. Sneezing every few minutes can be a sign of infectious bronchitis or IB, the most common of respiratory diseases. There is no treatment, and it may last a month or so, but it can affect most of the flock over several weeks.
Mycoplasma gallisepticum or MG can cause sneezing, watery or bubbly eyes, and sometimes swelling of the eyelid and conjunctivitis. Tylan 50 injectable used orally can treat it. Dosage is 0.2 ml per pound 2-3 times daily for 5 days. It spreads less easily than IB. Mycoplasma synovitis or MS is similar to MG, but can affect the leg joints causing swelling and pain.