Ferret off its food?

One of my ferrets seems to be losing weight and I am concerned she might not be feeding properly as she is much smaller than the rest of my ferrets. Can you suggest the cause of the problem?

Though it alarms many owners as their ferrets change in appearance in spring/summer, in the majority of cases it is due to the seasonal lifestyle, hormonal change and impending moult. Ferrets eat less food in the summer, as they are not as active as they are in the winter. In summer they spend a lot more time asleep or basking in warm weather, so need less food to sustain this change in lifestyle. You should monitor how much food your ferret has been eating, its general condition and energy levels. If you are alarmed, separate the animal and ensure that it is eating, otherwise seek the advice of a vet.