Scientists are studying Dolly the sheep’s “siblings” in order to study the health of cloned animals – and resolve a puzzle over whether they age normally.  “I’m feeling the joints for any kind of heat or swelling.”  Veterinary surgeon Dr Sandra Corr puts Daisy the sheep through a very hands-on physical examination.  “I’m looking for any signs of crepitus or lameness,” she says, “Anything that might indicate the onset of disease or osteoarthritis.”