I've just watched a lamb being born and its mother instantly up and walk away, without so much of a sniff. She hadn't returned after 30 minutes so I've given the lamb some artificial colostrum and some milk. They're now both in a pen together, and whilst signs are mixed, I'm not convinced that the mother is going to do the business. How long should I leave them penned together before I give up on the mother finding her instincts? Is she likely to hurt her lamb?