I have read someplace that Hillary was expected to lose Kentucky and therefore has pulled out this huge win.
Nothing could be further from the truth. Kentucky went huge for Clinton last time she ran there, and it was solidly pro-Clinton at the beginning of the primary process.
It is SANDERS who surged like crazy and came within a hair of capturing the state.
Kentucky is a HUGE Sanders win, and the party knows it.
She needed a win to keep up the illusion of her inevitability.