Inge - So glad you chimed in. I almost sent you a PM .I consider you to be our local mouse expert, just from the volume of mice produced and your awesome shed.

This colony was created 6 months ago with an initial purchase of 3 females and one male.

Learned right away not to introduce any new adults to a colony once it begins breeding and producing.

The ratio got out of balance by allowing too many of the male offspring to reach maturity.

Up until recently the mice were all well behaved, but I was starting to notice that there seemed to be only 3 mice feeding the "baby pile" remarkably 3 ladies can have so many litters so close together that it would be easy to think there were more females producing.

the other 2 colonies I have are created from (mostly) offspring from the first colony with only a couple fresh females added along the way. (Even noticed that introducing new females can sometimes have a violent outcome)

The first clue that something was out of balance, I had about a dozen hopper mice that had scruffy looking hair, were extremely undersized and just looked unhealthy all around. (Obviously malnourished)

The second colony was fairly new, and one young mom had just produced her fist (very small 4) litter, so we transferred a number of pinks/fuzzies over and she "adopted" them right away.

Things were looking a lot better for a moment, then she had her second litter, that took priority and she gave a bunch of barely weened babies "the boot" and exciled them to the other end of the tank.

We fed off the excess and tried to balance it back out. Seems to have worked, since all is well with that colony.

Started the third colony from the most robust of that batch, however some of them seem to have suffered stunted growth from lack of proper milk during development.

Any advice you may have to offer would be appreciated