After suffering a terrible brain injury from a concussion a while back which precipitated her need to wear Fresnel lens glasses, Hillary appears to also have problems with her lungs. No one knows this creature's true age, but judging from her easily-damaged brain and lack of lung capacity, it's anyone's guess. My guess is something akin to the age of Mr. Burns. Perhaps carbon dating could reveal her true age.
There is something very wrong with this woman. Once again (this time on February 26, 2016) she had another long coughing fit. I don't believe it was caused by the fall that damaged her brain. There appears to be something decidedly wrong with her lungs. Is (was?) she a smoker? Could it be tuberculosis? There should definitely be concern for her poor health.
She had no trouble barking like a dog a few days ago, though. Maybe it was just too much for her poor, old lungs: