ASF's being killed

I have a grow up tub and in the last batch of little ones I moved over 1 was found dead not I am wondering in your grow out tubs how far apart are the generations? I have 2 trio's going with one of the just starting. The older trio are throwing 8-12 pinkie per female the younger trio has thrown 4-6 pinks with one female giving me 1 litter so far and the other giving me 2 litters. Also how long to you leave the weanlings in with the parents before putting them in the grow out tub?

I have two giant tubs for my grow outs. 1 tub is for the just weined, the other is for all that are med or larger.

When their eyes are open and they are able to move around well they get pulled. No matter what you do, you will loose some here and there. Its the whole natural selection thing....

This happens with rats, mice, ASFs, etc...either they weren't strong enough to make it, or some social issue happened and they lost an argument.

I move my weanlings when I'm sure they're eating solid food well, and nursing less.