Over the past xx years I have seen many ferrets which have kept their winter coat until it is almost time to change in to the following years winter coat and vice versa I have had ferrets who have kept their summer coat until the following years summer coat was due, none of these ferrets have done it more than twice in their life time. Over the years I have been in contact with others who have had the same problem and I have found that 90% of the lack of changes of coat are from summer to winter and only 10% of the changes are from winter to summer. So their is nothing to worry about [Posted in FML issue 4722]