I have had three in the past year, and only one is a real "roller". :)
I dont know if they do this behavior less, more, or the same as hearing
counterparts.
 
Wolfy
 
Please visit:
http://www.geocities.com/wolfysluv/
for information on ferret deafness:
http://www.geocities.com/wolfysluv/deaf.html
[Posted in FML issue 3800]