Scratch is mix of grain very low protein........pellet and crumbles are a blend of grain with proper mixing.
Peafowl would rather eat the cheap scratch.(natural were pellet are not)...but its not good for them, the blend pellets is all they need. treats are ok ,as long as not to much.
Can they live on just scratch yes , but will not produce good eggs or health chicks. Just because they are living ,doesn't mean its ok to feed scratch.
Funny I don't know how many time I have hear about peoples birds not laying. Chicken,peahen,turkey and etc. then ask them what they are feeding ,,,scratch because its cheaper. I have told some to change to just layer....wow they start getting lots of eggs.