Minimizing feeder colony smell vs. litter size

I've been putting a few drops of vanilla into water bottles (5 or 6 drops/4oz.) and it cuts back on the smell of urine some. I've been doing this for a long time, but just now started thinking if it has a negative effects on litter size/ frequency with mice.
Only one tank of 5 (my youngest breeders) is getting just plain tap water. This tank has given me a litter every three weeks now, avg. 8 or 10 pups. These mice are all under 5 mos.
My other tanks w/ vanilla in their water, are 6-8 mos, and litters are usually large, like 10-12, but only have litters about 4-5 wks(maybe due to age tho).

The mice pups grow normally and have been healthy their whole lives after lots of generations and no bad effects on my snakes on the long-term using these feeders.

Does anyone have experience using vanilla and note anything about litter sizes/freq.?

I've tried the vanilla "trick" or myth, and it had no effect on the mouse odor.

It did, however, cause some nasty mold growth inside the water bottles.

Mouse odor isn;t an issue for me if I keep the density down, clean weekly and use a pelleted bedding. I'm currently using wood stove pellets, $4 per 40lb bag.

It could be wishful thinking and depending on an old wives' tale that has me believing vanilla in the water would do the trick. I spent an hour searching for any scientific data on the effect, and just came up with posts on reptile forums. Diet can affect litter size and frequency, though.

*sigh* yeah, regular cleaning is probably all one can do. Some tanks are aspen, the others that colored, fluffy newspaper bedding.

All of my rodents are on automatic drip systems. I tried putting vanilla in one of the water tanks a long time ago. It cause a mold to grow in the water tubes that plugged up all the drippers. I lost a few colonies before I realized they weren't getting any water.

I have been trying for some time to figure out an accurate way to rate colony production just like you omni. It gets really complicated. What I finally did with mice is set up all my colonies the same 1.5. Then I record how many mice I harvest every week from each colony with no regard to the age of the mice harvested. I then total it every 4 weeks and use that number to compare one colony to another. I average about 75 per colony per 4 weeks.

I like the harvest number because it reflects how well the male is doing at keeping the girls fat and happy but it also reflects how well the moms are doing at feeding and raising the babes.

Flagg, do you have a pic of one of your set ups with the wood stove pellets? I have been using that absorb an order bedding and it has worked okay, but it is a bit on the pricey side. I was looking for an alternative, but so far haven't found anything that I like.

Sorry, no pics currently. I use small lab breeder tubs with 1.2 mice in a tub. The top is a wire rack that holds the food and a water bottle.

The wood stove pellets are sold at Menards. When wet they break down into a coarse sawdust. It works just like other pelleted wood beddings like "Aspen Supreme" or "Woody Pet".

1 thin layer of pellets barely covering the floor works best, since it expands as it breaks down.

Try African Soft-furred Rats

They don't get much larger than mice, have more babies, and lack the smell of mice. On the downside, they like to bite.