Hi Vickylou, I'm a tad concerned. I get the impression that you have not kept sheep before - have you read any books on the subject? We can help on this forum but you do need to read up. Sheep need quite a lot of care. Feety trimming, worming, fly strike etc.
Are you keeping them for meat? If so, discourage your son from naming them!
Your sheep should be fine on grass alone at this time of year - unless you are trying to fatten them quickly for killing. Although it is handy to give them a handful of nuts in the bottom of a bucket once a week to keep them coming to you.