On a scale from one to ten, with ten being the easiest, Ringed Teal are an eleven. A great little duck but they breed like rabbits when content.
They need very little water and a very basic diet. So long as they are well kept and there's a selection of nest boxes high up in the enclosure you'll have them coming out of your ears in no time.
Let the hen sit and hatch her own eggs. Unlike most male ducks, male Ringed Teal help assist with rearing the young and the parents do a great job raising the young. Letting them raise the ducklings also (usually) stops them from laying again and prevents you from having too many of them on your hands come late summer. There's usually a glut of them available in the fall and selling them can sometimes take a while.
They are fairly easy to breed, they should have a small pond and raised woodduck style nest boxes give them several to choose from. Being a small duck they can be bullied easily and if they are not totally comfortable they will not breed.