Fluid in lungs - contagious?

Sadly, a few days ago we had to cull our RIR. About 2 months ago she started exhibiting symptoms of laying internally (floppy comb, watery/pale yellow stools, swollen abdomen, etc). At one point we didn't think she would pull through as it was clear she was fighting off some infection. Surprisingly though she lived through it but over the course of the next two months she lost a lot of weight despite eating normal and her stools continued to be extremely watery. A few days ago though she suddenly took a turn for the worse and had fluid build up in her lungs - at least I assume that was the cause of her severe gurgling.

This afternoon I went back there and the newest member of the bunch was sneezing quite a bit. There is no discharge coming from her nose and she seems to be acting normal but I'm just a little paranoid that maybe the RIR had caught something and now the other has it.

Is fluid on the lungs a result of the internal laying problem or could it be she came down with something? Currently we just have 2 hens in our backyard.