Sounds a good plan to me, Keir (oops sorry, wrong spelling - that's my grandson's name spelt that way) Kier If they are kept in teh same area all the time it can sour and you need to worm them often, so letting them out to free range is good - but can't you get Mum on board instead of deceiving her? I know I'd prefer that.
As to toys for them, big logs is good, and hanging things for them to peck at is good too.(Cabbages hung upside down) Mine have a little one foot high wall that they prance along on and hop on and off, as well as the remains of the last two Christmas trees!