Ok, 7 snakes to feed rats. 6 tubs available. If you think you would be able to switch them all over to FT, this will be 1000 times easier on you and the rats. I would expect anywhere from 9-14 pups in a litter, giving you from 18- 28 pups for a 3 week period. Stocking up will make it easier during times of feast and famine.

I would get 6 females and 2 males. With the 6 tubs, you have 3 levels, two tubs per each level. Start at the top, put the males into the top tubs. Leave them in for 3 weeks, pull them and put in the next level down.

After 3 more weeks pass, the weaners in level 1 get gassed, and thrown in the fridge. The males go from level 2 to the bottom most level. The girls in the top level get a break.

After 3 more weeks, the males get pulled, and go in the top level. Level number 2 gets the weaners pulled and gassed. Frozen for later.

Continue to cycle the males through the levels, 1 2 and 3, leaving them in for 3 weeks at a time. That should work out. Now, it's not guaranteed to be on time each week, but my colony is pretty reliable.

This should work if you have all of your snakes, or the majority on FT.

Just an idea for ya!