Good point about sudden switches, that is probably what is the deal so just give it a bit longer and just stop feeding it if he begins to vomit or has the runs. More poo than normal really isn’t a health issue at least. Hopefully it was settle down after another week.
Being young is pretty much a moot point, he’s at his new home now. Back some years ago, 6 weeks was the normal age to go to a new home. I imagine some of the old folks are still in the mind set as not everyone spends hours on the internet researching especially older folks!
