I kept hearing a chick peeping in the box. Nothing looked unusual. Being new, they sleep a lot. Then I looked really close, and notice that there was one that just wasn't moving around like the others. I sadly found that one of my BLR's is dying. It was doing great up until last night, I guess. I wonder why it is that by the 3rd day that some chicks don't make it beyond using the yolk? It hasn't happened to me often, but I haven noticed that some never will eat or drink, and will die once their reserve energy runs out. I also wonder if sometimes they don't have some kind of intestinal defect that would cause this.
I think my first chick died at day 5, and it might have been because the starter crumbs were too big. He cheeped all the time, and ran back and forth whenever he saw us. So try grinding the starter and see if that helps.
Sometimes it just happens. Defects in chicks is very common and many factors from parents health come into play too in how strong the chicks are. Just make sure they all know where food and water is and that is about as much as you can do. Starter should dissolve if they get enough water but sometimes there is one that just doesn't get it and you'll find a dehydrated chick straining. Shouldn't be a problem in small numbers though. Good luck with the rest.