Pet lambs need creep once out at grass so either make a creep feeder or feed them in a trough once or twice a day. Mine went out in the garden for a week then into the field, they’ve had hay for a few days but have now moved to a fresh paddock with the other ewes and lambs with just grass, creep feeder and mineral buckets. Best not to draw the weaning process out too long, they do better if abruptly weaned and less chance of bloat. I tend to wean off milk whilst still inside, leave them a week to adjust then start putting outside once satisfied they are eating creep and drinking water.