I stirred my chicken stock vigorously before straining it to get as much flavour from the solids. The flavour changed from mild to very chickeney but also a bit strange. It also became very brown and cloudy.
I used 1 roast chicken carcass including all bones and wings and boiled for an hour (I know it should be 3 hours but electricity/gas prices are expensive in Australia). It first seemed mild, then after stirring too strong so I added water, then made it into a Vietnamese style noodle soup the next day and it was mild again.
I've never had success with stocks.