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As Sasha said this is normal for older hams, at this time of year they can get a bit less active if the temperature begins to drop too especially when older.
If she's still eating ok then I would only offer porridge or baby food as an occasional treat, it is good for them but it's important she still mostly eats her main mix to keep those teeth trim.
Making any adjustments to the cage as & when necessary so she can get around easily & everything is within easy reach is a good idea too.