Fighting

My baby boy is now 7 months old and in the past two weeks seems to be pushing my old girls buttons and provoking a fight. Out of these fights most of it is just noise but twice blood has been drawn and not just his! these fights can happen not just at home but when out on a walk, although this mornings was over wanting the same toy. My old girl is pushing 13 and very arthritic but ŵon't take any nonsense from the pup. He has never fought with my four year old girl at all and has never met another dog he doesn't like. Is it him pushing her heriechy wise do you think? Recognising she's old? Just a phase? Afterwards he will try and curl up with her. Thank you in advance.

He's in the dreaded teenage stage. Pushing boundaries, listening to noone.

You need to go bk to basic training with him. Maby even up his exercise a bit more. When he is pestering your ol girl, step in early.
Separate him out of the room if needs be.

The teenage phase lasts as long as u let it !