Yup, I agree about not scruffing them when trying to introduce a new food. Sam will switch, she's already being adventurous. Mr B. will likely follow suit when he sees she is enjoying her food!
Don't use beef jerky - it has too much salt and spices. Most pet food stores now carry all sorts of dried meat items. But please read the labels, avoid ones that have added glucose or are not pure strips of meat.
I get dried chicken breast strips, duck breast strips, herring steaks, salmon pieces, pacific whiting. Freeze dried lamb lung and beef liver cubes.
The ones that are chopped and formed are also full of other things ferrets don't need. There's no sense getting them hooked on one thing only to switch them again. Introduce what you want them to be eating from the get go.
Unless you dehydrate your own cuts of meat, or freeze dry your own items you'll find that by reading labels of pet foods marked "all natural" its amazing how many of these "all natural" items have corn, wheat, and othe plant items added!
The dried items help in transition and as treats later, but shouldn't be considered a major part of their diet.
I am heartened that you will be joining the natural feeding program!
As a good look into why you should actually switch let's analyze a bit of what your ferrets have been getting so far. Hill's science diet is generally perceived and sold as a veterinarian approved commodity offering pets quality nutrition. But not really.
Their ingredient list shows a recipe of: Chicken By-Product Meal, Ground Whole Grain Corn, Animal Fat (preserved with mixed tocopherols and citric acid), Corn Gluten Meal, Brewers Rice, Chicken Liver Flavor, Fish Oil, Flaxseed, Dried Egg Product, Potassium Chloride, Soybean Mill Run, and a host of additives....
So there are five plant products in that recipe and the major ingredient is "chicken by-product meal". Chicken by-product can vary in quality from batch to batch. Chicken by-product costs less than chicken muscle meat and lacks the digestibility of chicken muscle meat. They add palatability and flavor with "animal fat" and fish oil.
Your ferret's system cannot digest the five plant products so you cannot count any nutritents from those sources.
Ferret Husbandry, Medicine And Surgery By John Henry Lewington writes that ferrets need a maintenance diet that offers 200 to 300 kcal per kg of ferret body weight. kcal means kilo calorie a kilo gram is 2.2 lbs, most ferrets in the ages of yours are either right at a pound or under a pound. You'd need to get your ferret's weights in grams to completely figure an exact MAINTENANCE requirement. But keep in mind your ferrets are young and still growing so will need probably at least a third more calories ( I'm still looking for kit kcal requirements).
Science diet kitten
www.hillspet.com/hillspet/products/productDetails.hjsp?HillsProductCode=SD_FL_D_ktn_NA_o_O_n_orig_USARG claims (510 kcal/per cup ² ) DRY. right there you can see that your ferret would have to ingest at least 3/4 of a cup of this stuff per day just for a maintenance diet! Most adult ferrets ingest 1/3 to 1/2 cup of dry kibble per day which means your ferret is in a consistent calorie deficit with this kibble! With your ferrets being young they'd have to eat at LEAST a cup per day of this stuff!
Because there are so many foreign substances ( foreign to the ferret's system) in that kibble you can easily see how over taxed their systems are to glean nutrients from such poor sources!
there are 5.5 kcal/gm of CBM (Chicken by-product meal) and 9.4 kcal/gm of animal fat which is basically the only thing in the science diet kitten that your ferret's system can digest. or IOW only 14.9 total kcal/gm available to your ferret.
There are 8 ounces in a cup,so that equals 227 grams.
If you could feed your ferret JUST CBM & Animal fat; one cup of this stuff would have 3382 kcal so 20 grams would offer 300 kcal, or just less than 3/4 of an ounce (.70 oz) !
When you do the math it puts into perspective how much garbage is actually in a bag of kibble compared to how much energy is produced!
An adult mouse offers 2.07 kcal/gm, the average adult mouse weighs around 25 grams so will yield 50 kcal per mouse. This means your ferret would need to eat 4 to 6 mice per day if fed only mice. Something an active ferret can easily do!
If you don't want to feed just mice its easy enough to offer your ferret necessary kcal per day by offering other whole prey items or natural raw meaty bones!
Granted ferrets need more than mere calories, but when you offer appropriate natural meaty bone items the ferret's system can easily utilize proper nutrients ( vitamins, minerals, calories) from them!
Kibble diets are an assault upon the ferret's system, forcing the ferret to eat tremendous quantities in order to try and satisfy basic requirements. Its just not possible to offer your ferrets an optimum diet from kibble!
Feeding natural is NOT that difficult and once your ferrets are eating NORMAL food you'll be proud of yourself for offering them a better chance at life!
Cheers,
Kim
has lactose, which ferrects can't digest (they get the runs from it). Cream has lots of fat and a lot less lactose.
also has lower amounts of lactose with less fat. (My brats are little oinkers 
and tend to gain more weight than they should)
Last I looked at the ZiwiPeak website, the ingredients and analyses were not listed. That was quite a while back, and the info is there now. I was kind of concerned about the chicory syrup being the number 2 ingredient, but it looks like there "Meat" includes organ. It's supposed to be a complete diet, but I didn't seen any mention of bone...May need to email my questions!