i am going to neuter my toby as well (he is 3 pounds so far) ..... i know that it stops them from marking, ect... and as for the hyper thing, its kinda a puppy thing isnt it? arent most puppies hyper? i know my toby has hyper moments but he also has quite moments.... as for up on the bed, i have toby up on the bed all the time (it is a double pillowtop so it is pretty high up) and he HAS fallen off a few times (because of his hyperactive play and not paying attention to where he is going) but he hasnt been hurt, just keep a good eye on him... as for the walking on teh leash, as with everything else just be vigilant.... as for the cold thing i really couldnt relate ( i live in california, and i have only had to put a sweater on him a few times when we have gone out at night)..... 4 and a half pounds isnt unusual, ive seem smaller yorkies very freequently...... and as for youre final question about the nipping, toby USED to do this as well, but he stopped doing it (to me at least) after the first day, i just gave him a gentle flick in the nose and a serious "No", it only took one day (but he still sometimes forgets when he is in "play mode" and needs a reminder)....... jackson is a cute name, post some picks, i would love to see them