Thats 100% puppy behavior, nothing odd there.
You are correct in only trying to engage him in 15 minutes of training, his attention span is still limited. Just like kids, when they get tired, they get fussy and puppy classes are SO stressful mentally for them. Not only are they under pressure but they are in a different unfamiliar environment and there are other dogs as distractions too! And when Rory was little, if she felt any frusteration or impatience from me she would lock up and fight me the whole way, ooh she used to be so stubborn. Its a battle of the wills, no doubt about it.
The icky runs he has been having could very well be do stress. I'm not implying that you are stressing him out but they can be stressed very easily. Please visit this site to learn about the stages they go through, fear, and stress....
[link
ti=PN&qi=2314]http://www.iams.com/en_BI/jhtmls/nutrition/sw_NutritionQuestions_qanswer.jhtml?li=en_BI&sc=D&bc=I&
ti=PN&qi=2314[/link]>http://www.iams.com/en_BI/jhtmls/nutrition/sw_NutritionQuestions_qanswer.jhtml?li=en_BI&sc=D&bc=I&
ti=PN&qi=2314]http://www.iams.com/en_BI/jhtmls/nutrition/sw_NutritionQuestions_qanswer.jhtml?li=en_BI&sc=D&bc=I&
ti=PN&qi=2314[/link]
It helped me so much when Rory was a pup to understand what might be going through her head.
As for the biting, you need to show him that it actually hurts. When he bites, yelp, yelp loud like a puppy, act startled and turn your attention away from the puppy for about 30 seconds (no longer, remember short attention span) that will tellyour puppy, "hey, that hurt, I dont wanna play when your mean" yelp loud enough to startle him, they first couple of times he may look at you like your crazy but eventually he'll see that he gets no attention if he acts like that.
Oh and sorry to be such a party pooper but this inst the las regression he'll go thriugh, you have the terrible post 1year teenager phase to go through where he'll pretend to forget everything you've worked so hard to teach him
After all that I would like to say congrats to you, it seems as if you are very mindful and caring of your pup. Dont get too discouraged, its how all puppies are and after the proper training you'll have a loyal, lovable companion who will greet you everday at the door with nothing but love, regardless of what you do or say!
The more time and training you put into your dog now, the better life the both of you will have. If he comes when he is called, then you'll be able to take him more places. If you teach him not to beg, you wont have to throw him outside everytime you eat or have dinner friends over. Keep us updated on his progress and good luck!