Short answer, you'll be fine. I never worry, occasionally you'll have problems. I do this at home and have had zero issues. I just got done with four litters all within a week or so, all four mothers were nursing young....despite if it was theirs or another mothers (all the young kind of got split up). All of the young grew and were health when I culled them. I think I lost one young (out of ~40), but that could have been due to a number of issues.