Melanie,
I have had similar experiences with my albino ferret, Blizzard.  She is a 4
year old that developed insulinoma within the past year.  I have found her
on numerous occasions in a very heavy sleep.  So heavy infact that the first
time, I thought she was dead.  I poked her, poked her more, began freaking
out and lifted her limp body out of her hamock.  As she lay limp in my arms,
she slowly opened her eyes and waves of releif come over me.  This was days
after the insulinoma diagnosis.
 
Even still, every once in a while, she won't get up.  I have to poke and
prod and go though the horrible feeling of thinking she is never waking up.
Only to have her open those little eyes.
 
Ferrets play hard and consequently sleep hard too.  I am not sure how normal
it is for ferrets to sleep that deeply, but I understand your concern.
 
*****************
Shelley Straight
VA-MD VET MED
*****************
[Posted in FML issue 1861]