Dunno if this is WAD, but butchering a child zombie gives normal meat.
And it does not decrease morale. (Killing children bad, but butchering them? Great more meat for the meat pile!).
The morale penalty also does not apply when you kill it at higher ranges (I got the morale penalty at distance 2 but not some higher distances, so might be WAD), by throwing a spear in it for example.