Today I bought some organic chicken gizzards to cook up and give to my English Mastiff Leo and my golden Retriever Molly. Leo is now 8 months and weighs close to 150lbs. While I had a piece in my hand, Leo jumped and took the meat out of my hand and pretty much bit 2 of my fingers, no blood or broken skin !! needless to say I was in shock and thought for sure I had 2 fingers missing !! He has never done this before. Is this normal for a English Mastiff ?