My 4 year old Daphne didn't come in for breakfast this morning when I checked on her she was on the ground still and wheezing gasping for air. I raced her to the vet, he had no idea and could only tell me her throat wasn't blocked. She died in my arms while at the vet. Please any idea what could have caused this. She was fine yesterday. I did give them new food yesterday which they seemed to love.