50#s should last you about 3 weeks with that amount of chicks that age. Maybe a little longer with scraps. You will see that time decrease over the next few weeks though. Their appetites grow faster than they do. I now have 21 chickens, all mostly grown and i'm going thru 50#s every 2 weeks, with moderate treats. I made my feeders from 3" PVC pipe and get no waste at all. Am working on getting details and pics for these feeders. Will follow up with instructions when i get the rest of my to do list done. LOL