Swollen eye with congestion could be a respiratory disease. It's important to know which one in order to know how best to proceed.
Would it be possible to take your hen to a vet to get a blood test to determine what the birds have?
Do a little reading on mycoplasma, infectious bronchitis, and...
Im not sure if I'm asking question in right place but I was wondering if anyone new what disease may cause my hen to sound congested and one eye to swell and if so what to treat her with