I am on my 3rd hen with water belly in the last 8 months. Why does this keep happening? My first to have it was an isa brown. My 2nd was also an isa brown she just passed a few days ago after her 2nd round of it. ( I drained her and she lived almost 3 more months until she got it again) now my leghorn has it. They are all 3.5 years old. Is this just something that happens with age or what?