Can orcas ever be healthy in captivity?

Last month SeaWorld announced it was ending its orca breeding programme and said the 29 orcas currently in its parks would be the last. But the company did not step back from its long-held claim that its orcas - also known as killer whales - live long healthy lives. Liz Bonnin was granted unique access to SeaWorld to investigate this claim and weigh the scientific evidence.