Ok, this little one looks to be very young. Like the other poster said, he needs to be warm. A red heat lamp and a thermometer are key here. Set the heat lamp up in a corner hanging above your box that the baby is in. Put the thermometer under it so you can make sure it doesn't get too warm. You want the little one to be able to get away from the heat if he needs to.
What kind of food do you have for him? Hard boil an egg, mash up the yolk, and see if you can get him to eat that.
Pick him up and dip his little beak into the water (don't go up to the nostrils!)
Try this several times. Mix some honey with the water or put a dab of honey on the tip of his beak with your finger. This might help give him a jump start.
Get some poly-vi-sol infant vitamins from the drug store, the kind without iron. Try giving the baby one drop on the beak line once a day.
Keep tapping your finger in the food and water to try and tempt the little one to eat and drink. Keep dipping its little beak gently in the honey water (or sugar water).
The heat lamp is very important, if you don't have one, get one ASAP. The chick needs to be kept at 95 degrees its first week of life, going down 5 degrees each week, and always with a way to get away from the heat if it needs to.
Also, check its little vent daily for "pasty butt". If poop builds up on the opening it will block the vent and the chick will die. Wipe gently with a warm wet cloth to clean it.
I had two weak chicks that almost died last year and this approach saved them.
Have you raised cchicks before? Do you have other chickens? This little one will need company.
Good luck!
Andrea