All my mice stopped producing all at once!

So for awhile I was literally over run with tons and tons of mice. I was feeding multiple mice per feeding to my bigger snakes just to get rid of them. I even removed the males from the female tanks and waited a bit and replaced them. Now it's been over a month and none of my females are producing, none of them even look pregnant! I'm thinking that they just got too old, they are all probably around 7-8 months old. Luckily I have some of their babies left, they are just a couple months old and fully mature.

I'm going to replace all my colonies by feeding them off one tank per week for three weeks and make some new groups of one male to four females, that should give me about 50 per week. And this time I'm going to freeze them at various sizes so I have some as a backup and some to sell. I actually haven't had any pinky mice for a month and I have snakes that will only eat pinky mice. Luckily I was feeding them heavy and even going a month without food they still look fat an happy LOL.

I would consider giving my females a break after each litter. Especially if some of the females are having back to back productions. They do need time to recover. I breed mice on a small scale to have feeders for my hatchlings and my adult male pied who is a mouser. One male to 3 female mice is what i downsized to. Each female is given 30 days off between litters.