Baby chick help

I'm watching my neighbor's chickens, and I noticed this little black chick not moving when I checked on them this morning, and just opening and closing her mouth.

I brought her back to my house, and I'm not sure what to do. She won't drink or eat food. Sitting with her now next to a heat lamp.

Have tried dipping her beak in some water with vitamins, putting a couple crumbles in her mouth, and she won't take them.

Any advice would be appreciated!