Older hen with breathing/respiratory issues. At a loss

[Wyorp Rock]

I kept up the Tylosin for the 5 days as instructed on the package, and she is much better during the day but is still sneezing and congested at night
Is there anything else I can do for her? The coop seems to be well ventilated and I put vitamins in her water.

Does she have any bloat or feeling of fluid in the abdomen below the vent between her legs?

It may be that she has a bit of fluid or if she also has some reproductive issues, pressure from roosting can sometimes cause some respiratory symptoms. It can be hard to know.

I'd check her crop and also feel of her abdomen for any bloat or feeling of fluid. Even though she's not laying eggs anymore, often as a hen ages they can have reproductive disorders that unfortunately will produce some symptoms of gurgling, labored breathing, etc. But if you are seeing mucous, that can point to respiratory infection.