He's probably like this because of what he usually eats. Chickens need chicken feed, they cannot live on rice. Rice has nowhere near the nutrition they need.Usally eat boiled rice wheat as main with other types mixed in
Sometimes as a treat hard boiled egg
Yes we can manage electrolyte
I suggest you get some chicken feed, it has everything they need in it.
Is the other chicken a rooster or a hen?
Do get the electrolytes in him.