Duck soup......
Quoting from the Ferret FAQ at Ferret Central, Ann Davis of ACME Ferrets has the following to say about Duck Soup:

For years, we have been trying to find a super formula to fatten up sick ferrets, oldsters and ferrets with ulcers. We have been looking for something high in calories and protein, with added vitamins. After trying just about everything on the market for pets, we had just about given up, and were making do with some things that were not quite perfect for the little guys, because everything made for cats that we could find had a condensed milk base. We have heard of many miraculous recoveries attributed to Duck Soup. It has helped old ferrets, ferrets with insulinoma, ferrets with hair loss, and ferrets who are just plain too sick to eat.

There are several variations on the original recipe; these are included below. However, there are ailment-specific recipes that attempt to address, through specific supplements and, frequently, herbal remedies, ailments such as lymphosarcoma and adrenal disease. Please see the special recipes page for more complex and involved recipes for ferrets with specific ailments.

However, plain ol' Duck Soup has many advantages, as stated by Ann above. Nursing sick ferrets back to health and putting weight on underweight ferrets is frequently necessary, and somewhere among the recipes listed below you should be able to find one that your ferrets fancy.
Preparation
It's best to have a blender with which to mix the ingredients. In a pinch, a coffee grinder will suffice to grind up *dry* kibble (no wet things in the coffee grinders, please!). If you are including dry kibble in the recipe, prepare it beforehand by soaking the required amount in just enough hot water to cover the amount of kibble; only put the kibble in the recipe after it's absorbed all the water it can. Not doing so will result in the consistency of your mixture changing considerably from first feeding to second, and you'll need to add more water later. Otherwise, the ingredients should all mix easily. It's generally agreed that the final mix should be heated before serving to the ferret -- see the reheating notes in Storage below.
Serving
Remember that ferrets are finicky eaters. While some ferrets will just chow this stuff down, some are a lot pickier and eat a lot less than you'd like them to eat. Aside from trying different blends to increase the palatability and tastiness for your ferret, I've included some hints on convincing your ferret that it wants to eat the goop you're trying to feed it:

Get the ferret to taste it first. Many ferrets won't eat anything they haven't already tasted, so dab a bit under their nose or pry their mouth open and plop a small dab on their tongue (this is easier than it sounds, but can get messy!).  Hand-feed. Ferrets LOVE to be hand-fed. Get a small bowl, a spoon, and a towel and sit there letting the ferret lick the goop off the spoon. The way that works best for me is to let the ferret lick the soup off my fingertip; they will NEVER refuse anything I offer to them that way. Use the towel to clean up when you're done. :)
     Ferrets don't eat and eat and eat, they eat, drink, wander a bit, eat a bit more, drink some, and run around. Don't try to feed the ferret all in one sitting - give yourself 30 minutes or so and feed the ferret in bits and pieces. This is the best method if you've got an active ferret that squirms a lot. If it's a sick ferret and isn't very energetic, remember to give it water/rest breaks every few minutes.
Storage
The easiest way to store the standard mix is to pour it into an ice cube tray or trays, cover it in saran wrap, and freeze. Pop out a cube for each serving. The stuff is HARD to get out of trays. Use an easy-pop tray or if you're good with a butter knife you can slide the blade between the cube and the tray and the cube will usually pop out. Do note that one cube may be too much soup for one feeding of one very picky ferret, but your mileage will certainly vary. To reheat the cubes, put one in a microwave safe bowl and pop it into the microwave for 30 seconds high, more if that doesn't defrost it entirely. Make sure you adequately stir the soup! Microwaves heat unevenly, so while you want to soup to be at least room temp, you don't want parts to be frozen and other parts to be boiling hot. You could seriously burn your ferret if you overheat the mix. If you overheat it, just set it aside and wait for it to cool.
Please click next to get recipies!
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