What does it mean when a chicken has bubbles in its eye?

look, I am only 12 but i know alot about chickens. At the moment one of my chickens has its eyes stuck shut and I dont know what to do. But one of my ducks had bubbles in its eye and it turned out that it just had something in its eye, so you could try getting warm water with salt in it and just rinse its eye out. Im not quit sure if my answer is correct but i hope iv helped.