As in V or or Y shaped while they are standing, you want to be able to feel the keel/breast bone. You want it to be a V shape, they are too skinny if that keel sticks out and feels like the back edges of a knife in addition to having the indent on the sides like the Y. They won't be anything...
I bet they are fine. I am assuming you have hatchery stock birds, so if that is the case, they will probably not ever reach 7.5 lbs, and even if they get there, they will be about 2 years old before reaching their full adult weight.