baby chick 2/3 weeks old swollen and lethargic

[jpinto]

First time having chicks..1 is our from our own hen and rooster, 2 from feed store. 1 from feed store has been very lethargic/sleepy last 2 days, has very swollen back side (gullet?) where intestines are. From everything I've read she is either constipated or has parasite. been giving electrolite water, moistened food, and molasses mixture for laxative - she takes all 3. have terro vet as well, but not sure on measurement. I thought she would have died already.. she hasn't improved or worsened. No bloody droppings. Though I'd try antibiotics now. Any recommendations?