Visit a local pond (or similar) to feed the ducks.
A pond or similar with ducks
Plenty of adult support for younger ones
Prior to activity, source a local area that has ducks and risk assess as appropriate, taking into account any slippy areas, how close members of the public will be to the young people, how many can get 'to the edge' in one go, how far out they will be spread whilst throwing and how many adults will be required to monitor. Recommend that especially with Beaver Scouts, alter ratio to at least 1:4 if possible.
Either store up bread or just as easy is to buy a few loaves on the day (couple of Â£)
Walk young people to the pond
Feed the ducks
If you have an area suitable nearby play Pooh Sticks, tell a story, play a game, have a picnic, whatever takes your fancy.
The walk to the duck pond can be fun too, covering road safety or even just answering questions about the local area.
* This activity can be perfectly safe if you are well prepared *