I've always had them out as soon as there jabbed, a pup will look to you for security
so it wont f*ck off on you like some adolescent dogs do, get it in amongst livestock as early as possible
if your ferreting make sure you net all the holes and when you think its ready find yourself a nice sett out in the open
get a longnet round it so your pup cant be dragged around it will have seen netted rabbits
so will soon catch on, its about building there confidence
they learn f*ck all sat in a kennel