I have read that if you stack too many on the carcass muskrats in the freezer at one time, that the cold air will not get to the center of the rats and that you will risk spoilage. Does anyone have any experience with this? I have always skinned my rats the same night that they were caught in the past. But as we all get older our energy levels drop off with age. Now I think I want to focus on trapping for a week at a time and then take a short break and skin everything at my leisure.

That is true.
No more than two layers thick or you risk spoilage.

I have always skinned right away as well when I caught rats-even if there were a few hundred. I have frozen them before but never so many that you'd have to worry about what you are talking about but I am thinking that YES you could definately lose some if they are not given ample space to freeze solid. One spring when I was young and energetic I bought about 1600 beaver in the round-would green skin them and into the freezers they would go layer after layer-well I lost quite a few of them to taint because the fur insulated them from freezing for a long time-lesson learned. Just saying.

But aside from the freezing solid thing-I found that when I skinned rats that had been frozen in the carcasse-they tended to tear apart easily and would often tear the carcasses in pieces to skin the rats-tenderized in a way I guess.

Is there any type of temporary spacer that you can place between each layer of rats and then remove when they are frozen like bricks?

Yep

I used to chop off their tails, but five per plastic grocery bag and place bags one layer deep in the freezer with good results. A spacer system would certainly allow for a second layer. The key is to get them surrounded by the cold air.

Ones you have a couple of layers frozen. You can stack those rats on end with the tails up. Now you have your spacer giving air flow. Stack more on top, as they freeze you con manipulate them to make air space.

Never had hundreds of rats in a short time,but good points from the posters so far.
Too much fur packed in a freezer is risky because of the insulating properties of fur and the time it takes to freeze the interior of the pile.
Rats frozen on the carcass are often a mess to skin after thawing.And if they are wet and not bagged they will be in a big frozen ice cube when time to thaw and skin.
If possible it would be best to skin as you go and freeze the skins.
Leaving air space between the furs or carcasses in the freezer will eliminate spoilage from overpacking the freezer with unfrozen stuff.

Skin and roll up with no leather side exposed i.e. fold so any leather side is inside. Have done that lots of times for up to a year and no problem. Will go about 6 months for skinned and cleaned skins rolled up same way before they start to show some signs of freezer drying but not a huge issue unless stored a lot longer.

Preferred way is put "put up" skins in boxes in freezer. Skins are packed nose to tail alternating and tight like crackers in a box. Got over 400 like that now and waiting for market to improve. Not worried about storage. Have few pieces of inch board in bottom of freezer, to keep boxes off bottom and away from any residual moisture, in case of break down. Not too worried about that even as skins are dried. Freezer is full with 'rats only and nothing that can thaw and produce moisture. Enough for now though and 'rat trapping put on hold until market improves.

I have in the past frozen a few rats for whatever reason and never noticed any difference while skinning.

That's the same experience I've had with freezing rats whole, they tear easy and can make a mess. All rats are skinned and then place the skinned hides in the freezer before I'm done for the day. Not to mention all the freezer space they take up.

Anything frozen and thawed turns a bit mushy. Can be worked with but more trouble. Also freezing and thawing whole animals promotes taint/hair slippage. Short story: Avoid freezing whole furbearers if you can.

Yes they can spoil but also the posts above regarding harder to skin is really accurate. I put up 200 for a person that were all frozen and they took twice as long or more to skin as they pulled apart so easy that it was a real chore k plus you get a lot more messy with the body fluids all over the place. Take the time to skin them right away. Put them in the frig for a day or two if you don't have the time. Freezing is not a good option for me at least.

Bryce

This, I have always noticed they get soft when they thaw. You can't pull thawed rats, they come apart. skin and freeze the fur.

we stack them 2 layers deep, always belly side up. then a spacer, and 2 more layers deep again. spacers are 2x4 frame that just fits the freezer, covered with 1x2 or 2x4 wire. they actually skin easier for us after having been frozen. the carcass will rip easier in the belly area, if you're pulling from the back forward. we skin with the method where you push the head back inside, then pull the hide back toward the hind legs. bellies wont rip this way. we'll never skin a fresh rat, even if we did have the time.

I found that skinning them out, stretch and place them in Vacuum pack bags and seal. I can stack 30-40 in a small area.

When fall comes and the price is up, open and let stand for 24 hours. Good as fresh. No freezer burn either.

Less chance of spoilage.

Unless your running your freezer for something else you would be losing money If It's just for freezing rats. LOl

That has been my finding as well

I still freeze them when I have to many to handle at one time, but I also make sure to clip the toes off the feet, if you haven’t found out yet the dang claws turn razor sharp when frozen

Yes, those frozen claws are lethal!

You can do a layer, then 12 hrs later do another layer and so on. The time between layers is time to lay them out (belly side up as fossil states) with the fan on them to get them dry. Once the belly fur is froze (don't have to be froze solid), you're good to go. Again, lay them in the freezer belly up. If you put them in dry, they will come out easily. Use gloves with frozen rats. For some reason they turn into Freddie Kruger and like to slice and dice you.

I freeze all mine carcass then take them out come January and do my fur work when the trapping is done. As fossil states, they peel easier once froze anyhow.

Having extra freezers on hand is the key, of course.

Now, I froze far more than 1 or two layers deep out in the Dakotas and had very minimal spoilage, but it's not ideal of course.