Yes, there is definitely a difference between freeze drying in the open and putting the meat in a baggie and allowing it to dry. the meat in the baggie will NOT dry, the baggie will retain the moisture within the meat and just freeze it.
You have to have a frost free freezer in order for the meats to actually get freeze DRIED. You'll know you have a frost free freezer either because it says so on the label, or because you do not have to physically defrost the freezer.
It MIGHT work in a regular freezer , but more than likely all that would happen is freezer burn.
So now you have your frost free freezer. I've been using ice cube trays and those styrofoam trays the meaty items come in.
Cut the meat into small pieces 1/4 inch thick by about 3/4 to an inch square. Place into the ice cube trays, I put up to three pieces per cube but not packed tightly - the idea is to allow air flow around the pieces. On the trays I place the pieces so they just barely touch each other.
Let these freeze for several days. Pop out the cube trays onto some wax paper or a cookie sheet and leave to freeze dry some more. You'll know the meat is drying because you can see the difference in the moisture level from where the meat was exposed to the freezing air and where it was not.
Depending on the moisture level of the original meat and it's fat content will determine how quickly the meat actually dries. Liver takes an interminably long time - several weeks to completely dry. And even then I wouldn't put it in my pocket for a day trip!
Chicken hearts I cut into thirds long wise, these dry fairly fast - generally by the end of the second week they are fine for day trips in your pocket.
I just leave the dried items in the freezer, but if you have sufficiently reduced the moisture levels so that you can tear or break apart the piece and see NO change in coloration from the dry exterior they'll be safe to put in an airtight, moisture proof container.
The speed with which the items dries also depends upon how much air flow is allowed around the pieces.
If you freeze dry items with bones in them you have to allow a long time and the pieces need to be fairly small.
Chicken necks cut into thirds or quartered work well so the piece is about 1/2 to 3/4 inch thick.
I have freeze dried:
Chicken necks, hearts, livers, meat, wing sections and drumsticks with large pieces of meat removed.
Chicken meat
Turkey meat
Salmon
Turkey necks
A ground meat mix of chicken turkey, beef, pork.
Lamb
Veal
Duck soup
And mashed pumpkin
The texture of the freeze dried meats will be rather like leather. This offers the ferret some decent teeth cleaning.
The nutrient quality of freeze dried is not that different from the original state. This chart offers some information on nutrient changes:
cleaneatingdiet.blogspot.com/search/label/Nutrient%20SavvyI reconstitute the duck soup before feeding, but the rest I just offer as is.
Freeze drying is a great way to stretch your food budget and still offer your ferrets beneficial meaty items!
You can offer ground meats that are freeze dried and because of the texture change they'll derive more oral benefits from eating freeze dried ground meats than moist ground meats!
The chicken heart pieces can be again torn in half and used as treats for trick training.
IF you buy in bulk and cut up some meaty items and bony items you can either immediately tart the freeze drying process, or baggie the cut pieces and choose to freeze dry them at a later date. For easy transfer place the moist cut items in the baggies and store them flat, push the pieces inside the baggie apart so they don't freeze into one big glob, and when you are ready to freeze dry them just cut open one face of the baggie! Freeze dry one side for several days, turn over and do the other side!
The more often you rotate the items, the faster they dry.
Just one more healthy addition to your arsenal to keep your ferrets healthy and happy!
Cheers,
Kim