I have 7 - 9 wk. old banty's. I still have probably 40# of medicated starter/grower left. Can I continue feeding this to them until it is gone, or will I need to change sooner. They are not eating it very fast, and I have it available 24/7. At the rate they are eating now this 40# will last until they reach probably 17 weeks. I was also wondering if I need to slowly introduce them to the next feed, or is it okay to do it all at once? Any information will be greatly appreciated.