Not from Kentucky but we get something similar out in parts of rural Hampshire that nobody can explain properly. The classic "fox scream" explanation only goes so far - when you've actually heard a fox you know there's a quality to it that's quite recognisable. What people describe in these Kentucky reports sounds different, more sustained and with almost a rhythmic quality to it.
Have you tried any EVP work or even just leaving a recorder out overnight? Sometimes the audio picks up things your brain filters out in the moment, gives you something more concrete to analyse.
There's a few possibilities worth considering - big cats (genuinely underreported in rural America), some kind of primate, or even acoustic weirdness from terrain doing strange things to distant sounds. But honestly the sustained screaming that doesn't match any known local species is the bit that gets me. What direction does it seem to come from, always the same area or moving around?