I just read this thread and there seems to be a few things I would like to help clarify. Your snakes seem small, but that could be due to a few things. It could be your feeding schedule. If your feeding once a week or so, that could cause them to gain weight a little slow. It could also be from a parasite. I would check into these things.
I think it might be from your heat setting. Your running your rack a little warm. Temps in the high 80s are OK. As long as it doesn't get warmer. But the warmer your babies are, the faster their metabolisms are going to be. They are going to burn more energy. I would listen to danielle and get those temps down to 85F, tops.
Also, when you thaw feeders, you have four hours to use that feeder, once it reaches the danger zone. The danger zone is a temp range that bacteria loves to grow in. That zone is from 41F - 140F. What you need to do is look at the clock when you begin to thaw. The only thing I would like to add to this is that this is safe food handling for humans.
Freezing does not kill bacteria, but slows its growth. The only way to kill bacteria is by cooking. That would require bringing the temperature of the feeder above 155F. I for one, am not going to start or try to cook feeders before feeding them to my snakes.
Refreezing. It's not unreasonable to think about refreezing a pinkie. I don't do it. Too many variables. I will present the logic behind it and let you decide for your self. As I mentioned before, freezing doesn't kill bacteria. It just stops it's growth.
Here is a scenario:
Let say you took out one pinkie to feed one snake. His name is Bob. You take Bob out of his viv and place him in his feeding bin, assuming you use one. You grab a pinkie out of the freezer and drop it in hot tap water. In about 10ish mins, that pinkie is no longer frozen. It's completely thawed and warmed up to about 100F. You place the pinkie in Bobs feeding bin and he doesn't eat it. It's the first time Bob hasn't eaten, so your not worried. You decide to leave Bob alone with the feeder for an hour. When you go back, Bob still hasn't eaten. So you put Bob back in his viv.
This is when you can make a choice. Now let's say you don't have another snake or any other animal that eats pinkies. Your only option is to throw it away, right?? Wrong!
Because the pinkie has only been in the danger zone for 1 hour 10 mins (10 mins thawing and 1 hour with Bob in the feeding bin), you have 2 hours and 50 mins left on the clock, before the animal begins to spoil. If you put the pinkie in the baggy all by itself, in the freezer. It should freeze in about 20 mins. If it doesn't freeze, you should still be fine, because the body temp of the feeder should be below 41F. By freezing bacteria stops growing and the feeder will not spoil.
In a weeks time, you can use this pinkie to feed Bob again, as long as you remember that you only have 2 hours 30 mins left on the clock. If Bob doesn't eat it this time, then you will probably not have enough time on the clock to refreeze it again. It's not unreasonable to think that you can refreeze a feeder. Once the four hour clock has passed, you must throw it away or cook it.
I don't. I have too many snakes that I could feed a feeder too. I'm not saying I haven't. When I first started out, I did do it a couple of times.
The real rule of thumb is, "when in doubt, throw it out!"
As long as you remember that, you should be fine.
As far as how long to keep feeders in the freezer. That is going to depend on how the feeders are packaged. A loosely packaged feeder is going to begin to freezer burn in about 3 months. If vacuum sealed, they could last as long a year. I would use your eyes and nose. Look for signs of freezer burn and smell it. Anything smell or look off, then refer back to the rule of thumb.
Just for an FYI, This is by no means scientific. This is based on my training as a chef. I, for about 15 years and before becoming a truck driver, held a certificate in "Safe Food Handling"
If you want, you can check what I wrote by visiting the FSIS.gov website or by clicking this link
http://www.fsis.usda.gov/factsheets/safe_food_handling_fact_sheets/index.asp
This information is always changing so it's a good idea to stay informed.
Wayne