So long as your dogs are steady with the ferrets mate ,then go for it.Only do the rat buries in soil to start with and fit the ferret with the micro ferret collar.Rat holes are a lot tighter than rabbit holes hense the need for the smaller collar.The innoculation thing is a shady area as I dont know whether they can be done against leptospirosis ,the rat spread killer.Most farms that have a bad rat problem are untidy and suggesting to the farmer to maybe move a few things like tyres ,bales,sheets of tin and stacked wood,shouldnt be a problem.Buries under concrete are best either smoked out or