My Lily is almost 4 months also. I feed her 3 times a day, very similar to your schedule. She eats it all up too! I read in a yorkie book that once the pup hits 6 months, you can change it to 2x a day( maybe like 9am and 5pm? Someone please correct me if i'm wrong. I also leave her water out all day. So far though, I think you're on the right track!
