Reserve sides in Lower Leagues

I think big Scottish teams should play reserve or under 21 sides in the lower divisions, up to League One. This would ensure that young players at the big clubs get competitive football experience at a young age.
They allow this sort of thing in the Netherlands, France, Germany, Spain, and Portugal.
This way young players at big clubs like Celtic, Rangers, Aberdeen, Hearts, Hibs, Dundee United and Motherwell could get a fast track to senior competitive football. It would not damage...

Reserve sides in Lower Leagues