We had a very similar problem when we first got Bebe & Jako.  The only
difference is that they were purchased the same day.  Bebe was actually
bigger at the time and used to give Jako problems; all that same behavior
you mentioned.  We did the scruffing discipline, telling her no, no.
After a while it stopped.  In later years Jako got bigger and gave it
right back.  In the end though, Bebe was right by Jako as he got sicker,
keeping him warm and clean.  As long as no blood is drawn, I think they
should be ok.
 
James, Melissa & Kassidy
Loving:  Bebe, Riley
Missing:  Wheezer, Pym, Rikki, Jako
[Posted in FML issue 4173]