Corn snake has shed but won't eat?

My grandmother's corn snake shed recently, but has refused mice for the past few weeks. She is active, having gotten loose recently, so she doesn't seem to be ill. What might be some reasons she's off her feed?

2018-08-18T02:57:39Z

Snake stats:
-around 3' long
-wild caught when young
-female
-possibly 20 years old (I'm in my 30s and I remember my grandma getting the snake when I was a preteen or teenager)

Anonymous2018-08-22T12:36:39Z

1.The snake may have been dehydrated during their shedding cycle causing an incomplete shedding.
2. The snake is simply not hungry due to possibly having been fed too recently.
3. The snake might be agitated due to over handling prior to being fed.
4.A fussy corn snake might refuse food which is not warm enough.
5.The snake may be to cold and will know instinctively not to eat.
6.The food may have lost it's odour due to being defrosted in hot water.
7. The snake may have a digestion problem and be unable to eat, regardless of being hungry.
8.The food on offer might be to large for the snake, leaving the snake unwilling to attempt eating it.
9. The environment the snake is kept in may have changed, leaving the snake nervous or anxious.
This could be any one of many things, such as:
Loud music or other loud noises causing vibrations within their vivarium.
Their environment becoming too hot or too cold due to being moved to another room.