For me communal mothering is a big no, common sense tells me I want to know which jill produced which kit incase of any defects so the jill can be removed from any breeding program
I have read that people mark kits from one litter with all sorts of things like tipex etc, to much fannying around for my liking, so I would simply seperate the jills & allow them to mother there kits as nature intended , just my personal opinion