“Jurors have been instructed that they’re unable to move onto deliberating the lesser charge of negligent homicide until and unless Penny is acquitted of manslaughter.”
I think at least a few jurors are aware that Penny will not survive prison, and will refuse to convict.
According to the Fox report, the judge is indicating that if they are deadlocked on the most serious charge, he will have to declare a mistrial on both counts.