For 3 birds I'm guessing you are overtreating. I give all our table scraps but I have anywhere from 40-100 birds.
There is no problem with sticking with feed only for most days. If you think about it, the feed is formulated to be a complete feed. As healthy as your treats may be - which they are, you are still skewing the total nutritional makeup. When giving grains and scratch, keep in mind that feed is mostly grain so you are diluting the added vitamins, minerals and amino acids.
The sleeping in a pile may just be because they are young or it got too dark too fast for them to roost.