I got my 5 free from a local farmer free of charge they where born the first week in april
when would be the best time to send them off ?
It depends on breeding and feeding; you want to send them off when they're ready, not at a particular age.
They're ready when they're fit - not fat - when you measure them on the tailbones, the loins and across the shoulders. You should be able to feel the tips of the vertebrae but not easily. If you can feel knobbly bony bits easily, they're not ready yet. If you can feel more than the tips of the bony processes, they're not ready yet. If you have to press really hard to feel any bone at all, they're too fat.
Few lambs will be ready in less than 14 weeks, most will take 5-6 months, some (most hill breeds and primitives) need a winter and second spring under their belts.
HTH. Do you know what breed yours are?