
Ok do either of them cock to mark outside and if so, how old and who started first.
My current 'wild guess' is that the staffy is not a particularly mature dog for his age, the youngster has just started to scent mark and this has pushed the staff into doign the same.(this could be the other way round though)
If they are both not particularly secure with where they stand with one another, then scent marking in the house especially if they are marking and remarking over the top of one anothers marks would make sense.
Neutering may help..... neutering may not make a blind bit of difference - ive got a neutered male here who, if stressed or insecure, will scent mark in the house.
For those reasons as well, i belive using a belly band (where the idea is you teach the dog not to mark whilst wearing it as its unpleasant) is unfair and not particularly kind if there are underlying reasons why the dogs are marking in the house and if it is scent marking and not toiletting, then there will be reasons.
Its not especially odd for dogs to mature later, in fact i think its more odd that we expect them to be mature far sooner than this. I wouldnt class many dogs under 2 years old as being mature adults at all.
Em