Emsworth is not short of ducks and of course swans which have always been associated with the town. The ducks seem to prefer the slipper millpond along Bridgefoot Path and there's a small slipway half way down the road which is a popular feeding spot. There's a few benches and a pedestrianised area which will be safe for little ones.
Another good spot for feeding is the Slipper Millpond causeway by the Sipper Sailing Club. This is the hang out of most of the local swans looking for treats from the passing walkers.
What you feed the ducks is of course contentious, the locals, environmentalist and animal lovers would prefer you feed them grain ideally, which you can buy from the Hardware Store and also Flintstones cafe, just at the bottom of Bridgefoot Path.