Week old Dominique chick sick, breathing hard

[JulieS]

One week old Domimique chick sick, littler than the other 5 of same breed. Only one that appears sick out of 11 chicks. Wings drooping, will stand with eyes closed mostly. She would open her eyes when other chicks bump into her but didn't move much. She would let us pick her up and hold her, not try to get away like the other chicks. Separated her from others tonight. She's in a box by herself in the house with heat lamp, food and water which she hasn't touched. She appears to be breathing hard. Noticed runny milk chocolate-colored poop the last two days that didn't look like the normal chick poo. She ate a little out of our hands this morning but haven't seen her drink any water even though we tried to dip her beak so she knew where it was. We have turkey poults in the same brooder but on the other side of a wire partition. We also have year old chickens in an adjoining coop but it's separated by a wood wall. Any information on what to do would be helpful, we're fairly new to chickens.