Could my ferret be overweight?

Question
Hi
I have 2 ferrets about a year in age (male and female), and they both are
healthy and in great condition, although my male ferret I believe may be
overweight. They both eat a mixture of Innova Evo Ferret Food as well as Drs.
Foster & Smith's Natural Choice Ferret Food. He tends to eat more than her,
but they both get over 3 hours of exercise a day with me, and they are free
roaming all day/night long.
He has a "bowling pin" body, and seems to keep gaining weight slowly, I
admit he is a big boy but when I scruff him he has a pretty bulky lower end!
I know your not supposed to limit the intake of their food, and I dont they
have a plethora of food 24/7, and I don't want to change their food since they
are pretty finicky eaters plus I like the food they are on and I believe its a very
healthy choice.

My question is what would constitute a ferret being overweight, and what can
I do about it? They have an annual exam coming up pretty soon and I will
bring this to my vets attention then of course, but in the mean time I was
wondering if this is at all common or you have seen cases like this, and if I
can do anything or I should be worried?

Answer
Hello Christina!

Ferrets are not like cats and dogs in that you have to worry about them becoming overweight.  They should have access to food at all times, and as long as you are feeding a high quality food, you should not be concerned with weight gain.  Remember, ferrets need to eat every 4-6 hours to maintain their high metabolism.

It is important to remember that males tend to be MUCH larger than females anyway, and any ferret's weight can flux with the change of seasons by as much as a pound.  My big guy is almost 4 lbs right now! Some ferrets are just couch potatoes while others are so skinny but also perfectly healthy!  

I do have a question for you.  What food are you using?  I could help determine if it is appropriate.  Ferrets require a VERY specific diet, and most pet foods (even ferret brands) are unhealthy.  

If you would like more info on food, please visit the link below for a question I answered for someone regarding diet.  

http://en.allexperts.com/q/Ferrets-2277/2008/6/food-ferrets.htm  

-Cindy P.