(You tell age by dental eruption.)
 
Even this method is unreliable if the mother was fed incorrectly when
carrying or feeding the kits, mothers having a very large litter can have
problems feeding which can cause retarded kit development.  I think this
is probably the main cause of small underdeveloped 8 week old kits that
appear for sale from time to time.  Chris
 
The Wessex Ferret Club      www.ferrets-r-us.co.uk
[Posted in FML issue 3792]