I'd treat for coccida if it's a concern, but since they are on the ground, treatment will never really eradicate the problem (it's caused by a protozoa that can live in soil) So you would be looking at routine treatments in order to keep your herd healthy. Feeding high tannin plants is said to help keep it under control (raspberry, rose, willow, etc), but my copy of Rabbit Production also warns about too much tannin, so balance must be found..
Some have chosen to breed towards resistance to that as well, and overall success seems to have a lot to do with how nasty their particular strain is. The hepatic cocci that hit my colony weanlings years ago was so nasty that I simply butchered what was left of the survivors and found another use for the pen.
To this day I've still never considered putting rabbits in there again. I probably never will.
Others have said that they have never actually had it kill kits, so they could just select from the strongest and go from there. :shrug:
I think, on RT it's most common to post a new topic any time that your rabbits have an illness that requires immediate treatment or action so that everyone knows to respond right away and to keep on eye on that thread. (and please put URGENT or something similar in the title so people know the buns are on a time limit.)