I don't have the exact time-line for ferrets but I do have information for dogs. Remember that ferrets have faster metabolism action than dogs so the time-line would need to be adjusted. When food is deprived, biochemical functions changes occur. In the dog, this process begins within twenty-four hours. The highest priority of the metabolic processes is to keep the blood glucose concentration at a normal level. If the blood glucose (blood sugar) level drops too low for any reason, the brain, heart, muscles and kidney function shuts down rapidly and death comes quickly. When the animal has no opportunity to eat, in ferrets this would mean no opportunity to eat the food they are perceive as food or are familiar with, the body will take stored glucose from the liver first, then from muscle reserves, This is done by changing the biochemical processes to different chemical pathways that make glucose readily available. After about two days the liver reserves of glycogen (glucose) will be depleted in the dog. In order to keep the blood level of glucose in the normal range, new chemical pathways open, called gluconeogenesis, where the liver and kidneys create molecules from complicated biochemical reactions so that fats and proteins are extracted from adipose tissue and muscle. As the glucose reserves are tapped and diminished, chemical reactions kick in to create glucose internally from those protein and fat reserves. Energy to run the bodys machinery (muscle, brain, kidney, heart and other organ functions require energy to fuel their activities) is now fueled less by glucose and more by fatty acid extracted from fat reserves. On the third day of food deprivation the metabolism (metabolism refers to all the chemical reactions going on to maintain life) slows down. (This occurs in people when not enough calories are consumed as in dieting and not consuming what the body needs - our metabolism slows down.) This lower, or slowed metabolic rate continues as long as no food is consumed. The lowered metabolism is a survival mechanism to decrease the utilization of body fat and muscle for energy. Lowered blood sugar levels changes insulin secretion by the pancreas (with ferrets being prone to insulinoma, this is hazardous) which in turn lowers thyroid hormone levels; and it's the thyroid gland function that ultimately dictates the metabolic rate. During starvation the liver releases chemicals called ketones into the blood stream; ketones are then used as a source of energy for the body cells. By creating ketones and fatty acids to be used as energy sources, the body conserves what little glucose is circulating so that glucose-dependent red blood cells and important kidney tissues can continue to access glucose. Red blood cells and kidney tubule cells cannot utilize anything other than glucose for cell energy needs. Personally, I could never let a ferret go 24 hours without eating. I care for old and ailing ferrets and many times it is a syringe of recipe every hour or so when they are not eating on their own. When they have surgeries I feed them at 4am and feel terribly guilty when I can't allow them to eat with the group at 6am. Ferrets depend on us for everything. Personally, I have and always will recommend slow food changes, whether it is kibble or what is referred to as natural. Ferrets arent like dogs. They wont necessarily eat whatever is available when they are hungry. Ive seen the deadly results of the is misconception. I have heartbreaking times in trying to find a food that a new kid will eat when I have no idea of what they did eat. Because ferrets are sensory animals, they imprint on the foods they have been fed and do not recognize other types of foods as food. This is why I serve 20+ kibble choices. Warm hugs to all. tle [Posted in FML issue 5206]