Okay. I'm sorry but I did not know I was communicating with a minor. I thought you were an adult. I know nothing about Malaysia and the veterinary care available there. I realize you would never neglect a living creature in a hot car on purpose but sometimes people need to leave cars and don't realize how hot they can get so quickly. Understand that I had no idea how old you were, how much control you have over whether you can take Cico to a vet, whether you drive, whether you can afford it, etc. Are you driving around Malaysia yourself or with parents or guardians? Anyone who can help you?
Regarding final feeding times, in nature, parent birds try to feed their babies right up until they can no longer find food for them because it's too dark out or the parents no longer have any food in their crops to regurgitate. If the babies are begging, the parents will feed them until they can't. Then the family goes to sleep. The final feed is as late as possible for the parents because the babies need to be fed often.
Anyway, I don't know what else to tell you. It doesn't sound like you have done anything wrong. Cico may still be fine. He's not a very young chick- he's at least four weeks now I believe, and I don't think he will die if he goes one day without food at this age. He has quite a bit of body mass and there's still food in his digestive system or he wouldn't be pooping. Try to get him to take some warm water and very gently message his crop down near the bottom to make sure there isn't some mass of food blocking the outlet of his crop.