I have a 15 week old collie puppy named Colt. We acquired him at the young age of 6 weeks from a house breeder who didn't know what he was doing - unfortunately, neither did we!! Now we know that those last two weeks with Mom and littermates were soooo important!! I have since done a lot to educate myself to not only the breed but raising a puppy in general. Colt is doing GREAT except in 1 area - biting!! It seems Colt likes to get his way regarding walks and play. When either are ended he becomes very agressive - biting and growling and pulling at the leash. He also does this to try to get us to play. Our reaction so far has been to give him a timeout in the kitchen (or in the crate if we need to be in the kitchen). Usually, he falls asleep, occasionally he protests. If we let him out after say 5 minutes he usually does the same thing again - he's doesn't seem to be getting it. He will come right up and bite our feet to get attention!! And honestly, we don't give it to him - he is put away without a word. We never play rough or tug of war or any of that stuff. He seems bored with the way we play though. He has ample time outside and we walk him 2-3 times a day. I do not work outside the home so he is not lonely or isolated. He is completely housebroken, has mastered sit, down, come, potty's on command, sleeps through the night in his crate in our bedroom without protest - he is Brilliant!!! He shows no territorial agression with toys, food, etc. But he needs to stop this agressiveness!! He is well socialized as we have many dogs in the neighborhood and he behaves very well with them. Oh, he also will hump my leg to try to get my attention - I gently kick him off and put him in timeout if he continues - never making eye contact. Please help!! We absolutely love this dog but we are really concerned. If this is normal behavior, how long can we expect it to last? How old will he be before he can be with us and not have to be put away? How do you feel about using a halti during walks to try and help?