I would make sure he gets checked for B12 and D deficiencies at the minmium. Ferritin is a storage protein for iron. If it is low, it could mean his iron needs are currently being met by robbing from storage but the storage is not being replenished. I find it interesting that his fatigue set in during the winter months. If you live in a northern latitude or where there is a lot of cloudy weather during t he winter months, your husband could be experiencing low vitamin D levels. Even aside from geography and climate considerations, people who spend most of their time indoors are often vitamin D deficient. Low vitamin D levels is a chronic problem in developed countries where people's livelihoods...