I've noticed some odd things about the 2 different groups.

The older group is the original group I got.
They have so far killed a third adult female that was with them when I bought them.
Killed the entire first litter (with me, not sure if they produced before me).
Killed an occasional baby(not sure if the adults did it, or the other babies).
When weaned their babies have killed other babies from same group. (In grow out tank)
Drink a bottle of water every other day. (Now have two bottles so we'll see)
Chew like crazy!

The second group of 1.2 are hold backs from older group out of their second litter.
Since weaned just the 1.2 in a 10 gallon tank.
Hardly drink (I could probably go a week without filling the bottle but don't).
Still have the original chew sticks I gave them as weanlings.
Have now had their first litter of babies and zero deaths. (They are about to be weaned)

Now I haven't moved the second groups babies to a grow out tub yet, but I'm tempted to put them in a separate tub just to see if I have any deaths in there like I have had with the first groups babies.

I can say they have all always had plenty of food and water. I check 2 times a day and probably waste food to make sure they have enough. So I'm not sure why there would be such a difference in the groups? My only guess is one of the females from the original group doesn't produce the best babies. And those are the ones causing the problems. Just my theory. None of it is really enough for me to say forget it and feed the original group off as I have been getting good numbers from that group even with the deaths.

But was just wondering if anyone else ever noticed anything like this? Or maybe it's something else that I'm not thinking of. Suggestions?

Thanks!