Carroll by Kathi S. Barton

Carroll Golden and his five brothers were the first of their kind. Born leopards, they were blessed with the magic of being the first leopard shifters. Morgan, their mother by proxy, raised them to blend in with humans and to be good men. Blessed with immortality, they all lived together on Morgan’s Leap, a sanctuary for all nature.
Hanna March worked for the FDA. She had always wanted to visit Morgan’s Leap, but it was closed to the public, so when she was given the opportunity to inspect their orchard on some bogus complaint, she jumped at the chance. The place was beyond anything she ever expected, and Morgan was the perfect host. But when someone took a pot shot at Morgan from the field, a huge leopard came out of nowhere and took them both down. Hanna, hitting her head on the way to the ground, was down for the count.
Carroll shifted back to human as soon as the women were out of danger, but finding out the pretty FDA agent was his mate took Carroll by surprise, and boy was she going to be mad when she woke up.