Close to laying pullets often start making weird noises and that's what I was initially hoping for, but "as they breath" really changes the possibilities.. (I can barely make it out for sure, but think I honed in on croaky-ness in every breath)
Congestive heart failure can be
one cause of fluid on the lungs.. and would not be uncommon to see in said breed. Some do live longer.. but it can be luck of the draw sometimes coupled with management practices (restrictive diet, etc).
Many respiratory infections may sound like that as well.
What other symptoms are you seeing? Is she actively eating and drinking on her own, still responding to treats? Any eye or nasal discharge, active sneezing, etc? Are you able to feel for "water belly" and would you (
or I) be able to tell it apart from standard abdomen chub?
Have you tried to look inside her beak to see if there are any plaques or other foreign objects aside from offering the water to try and wash anything down?
Just trying to help trouble shoot here. Hope you get answers and she recovers quickly!