Swollen sinus

[kabhyper1]

Edited to consult with vet so as not to jump to conclusions. Thank you for your response.

 

[Eggcessive]

Even though your avian vet ruled out mycoplasma, I think she has that or something similar. A nasal swab or other test my be performed, but not after she has been treated with Tylan. Culling may not be an option, but this chicken may have made carriers of your flock. I would speak to your state vet about getting tested. Your flock may be carriers, so I would close the flock to new birds or to any birds being sold. Here is a link to your state vet: http://www.aphis.usda.gov/animal_health/animal_dis_spec/poultry/states/indiana.pdf