a true and honest answer romany as always mate , i have heard and known of this before, again it worked, but to some this would been seen as cruelty in today's world.
some of the old ways still have a place and work well.
i have seen someone rub the ass of a killed ferret in to the nose of the killing dog,
then put the ferret around the dogs neck for a couple of days, rubbing its nose every so often with the ass of the dead ferret.
Sorry to hear about the loss of the kits, i hope things work out for you