I took Becks puppy training for the first time tonight and there was another Westie there who was six months, (Becks is four,) this Westie was twice the size of my boy and now Im worried that he isnt growing enough. Also Becks is quite short coated still and this other Westie had a mass of fluffy white hair. Should I be worried? Also Becks has devoloped a brown stripe down his back which I had been told was common when you de-fleed them, is this right?