What are those Barbarian villages?
You can recognize abandoned villages as they are named "barbarian villages". There is no difference between villages owned by players and abandoned and barbarian villages. The moral for empty villages is always 100%. You can take over empty villages just like any other. Although barbarian villages have no owner, they will grow to a certain size if the world settings allow.
When players are deleted due to an infraction or due to them deleting their account, their villages turn into barbarian villages. Sometimes units are placed in barbarian villages that formerly belonged to an infracted player.
Barbarian Villages are not affected by night bonus!