As a clan we feel that the requirement to continually feed thralls sounds like it will be a really repetative bind. As an alternative i think the below would be more fun.
Thralls placed at particular work stations generate a ‘food budget’. These could be stations like animal pens, dirt fields, fishing nets or hunters bench. Your food budget determines how many thralls you can support. That way, if the station decays by the usual decay timer, the thralls it supports will also die.
Just an idea!