I take photos of my kits at weekly intervals so you can get a general idea
of what they look like etc.
 
Now, ferret kits grow *rapidly* until they are around four - six months of
age, then slow down until they reach full growth.  a six week old kit can
fit in the palm of your hand if it has been fed well and looked after
properly, and the explosion of growth after then cam make it *seem* like
that kit had to be three or four weeks of age rather than six!  I know of
many vets who have seen seven week old kits and sworn blue that they were
only four weeks of age - as they were comparing their growth rate with
that of kittens and/or puppies.
 
Take a peek at the teeth too, at eight weeks of age, the kits will already
have some adult teeth in, which helps to identify the true age.  I'll give
you the address of a page I have on the Ferrets In Need site which includes
the ages of tooth eruption also.
 
Tooth Eruption: http://users.1st.net/hammock/ferrets/teeth.htm
 
Kit pages: http://users.1st.net/hammock/ferrets/kits/
 
I would recommend visiting the pictures for 1999 or 2000 - simply to ensure
the true ages are known.  Size doesn't necessarily give the 'age' of the
kits.  Several factors can stunt their growth, and some grow in spurts
which may make them appear smaller than the others.
 
I hope this helps!
 
Sam
[Posted in FML issue 3128]