Units with 30 morale seem unaffected by penalties such as starving and bonuses such as blessed. No matter what the environment the stats in battle always show 30. I don't know if that's a bug... but it seems like it.
According to the modding manual "Undead units with mentality but nothing to lose are usually given a morale of 30. They will not break but do not recieve Mindless status."
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