Ferret lost weight?

Haha I know I have a post on here about one of my ferts being too fat right now, but I'm also having the opposite problem! Nymphadora seems to have lost some weight (though I haven't weighed her, she's visibly skinnier and feels skinnier). She's by no means too skinny - she was a bit chubby before. She's getting older; she's about 6.5 and INCREDIBLY spry. Moreso than a lot of the (slightly) younger ones. I haven't been carely monitoring her food intake but I have seen her eating a lot. Has anyone else had a ferret lose weight as they got a bit older, or could this be a health issue? She has insulinoma, treated with pred, but as I said is very active and is eating.

It might be a good idea to check her weight.  Rapid weight loss is usually not good, and weighing weekly would give you an idea how much she is losing. I have some whose weights fluctuate seasonally, but they usually are putting a little on this time of year.. 

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