We have 5 chicks who are all 4 weeks old. Four are Buff Orpingtons and the fifth chick's breed is unknown--she came from my child's classroom at school. At week 2, everyone was doing fantastic. At week 3, classroom chick and 3 of the Orpingtons were doing great, but 1 of the Orpingtons became somewhat lethargic and began losing weight rather than gaining. She also had a tinge of blood in her droppings one day. The "chicken expert" at our local farm supply store told me to give them medicated water for 6 days (the medication is sulfadimethoxine) to treat them all for coccidiosis. Sick chick was still eating and drinking just as she always had. They are on chick starter but they have grit available at all times because they love going outside each day for short periods. We watch them very closely outdoors as there is a flock of vultures that enjoys watching them, too. Little chick has only ever eaten a fly that she caught. No other insects, no grass or other plant material. Everyone else pigs out on flies and nibbles on the tips of the grass blades. On day 2 of the medicated water, I didn't see her crop enlarging and had not been able to see her eating on her own. I made her some mash (just their starter with some of that medicated water). She loved it and for being lethargic and potentially not feeling well, she ate it pretty well for me off of a spoon. We also got some small meal worms for the others and when sicky saw them eating them, she went crazy and wanted out of our hands so she could get a mealworm, too. She ate 2 and was very happy with herself. She was really wanting to be held and cuddled, which I did for 1/2 hour and then she wanted down to get a drink and she also got some grit at that time. (She refused to take the grit even from my fingers immediately after eating the mealworm.) The next day, she seemed slightly less lethargic and a little more willing to eat the starter mash from the spoon. I watched to make sure she ate a bit of grit, also. Then, she pooped out her 2 mealworms . . . still intact, but darker in color than when they went in. Her poo was mostly watery with some white, but no sign of blood. By day 4 of the medicated water, her poo was back to normal--looked perfect. And she was wanting to move around with the others more when outdoors. Today is day 6 (the last day) of the medicated water, and sicky is much more energetic and is back to eating their dry starter and she drinks well and she gets grit on her own. Her poo still looks excellent. The problem is . . . she is still losing weight! Last week, she had lost 1/10th of an ounce . . . she was sick, so that makes sense. But, this week, she has lost another 2/10th of an ounce! I don't know how she's still kickin' to be honest. Everyone else's weight gain is fantastic. One of the other Orps is very small compared to the other chicks, but her weight gain is steady and she is happy and active. What can I do for little sicky to help her gain weight? I'm getting very worried about her. I have been watching them eat and no one is preventing her from eating . . . the 5 are actually getting along beautifully. Our biggest one sometimes steps on the others in her excitement to chase spots of light in the brooder and wandering flies, but everyone is being allowed free access to the food. I'm always prepared for baby animals to die--just in case . . . but, this is week 4 so it would be quite a shame to lose her after this long and with the improvements we've had now.