We have a 5 month old female golden lab. She's lovely but at puppy class she is by far with most hyper puppy. She won't sit still for more than 30 seconds. She has no concentration during any of the tasks. At home she is calm but gets easily excited. She has loads of toys and we constantly reinforce good behaviour with treats but it is completely exhausting and she seems to remain extremely hyper. She is fine on walks but once she sees another dog she goes manic. She has now started jumping up at us and she is toy possessive. Any advice on how to tire her out? Keep her more controlled? Any help gratefully received.