Lethargy week old chicks

[Phwaah]

Hello everyone

I am a new chook owner. I only just got my first 6 chicks last weekend and unfortunately one has already passed. She was very lethargic and someone had notified me that she likely died from coccidiosis. So I went to get some amprolium solution to treat the rest of the flock. But now another one is very lethargic again and I'm scared she is going to end in the same fate. I took her out for a while and fed her some raw egg yolk but she did not proactively eat any. I was wondering if there is something else I can do? I don't want to lose another one.
I was told they are leghorns and australorp but I think the white ones are actually Austra whites. They're all about a week old. The lethargic one has poop that seems a bit runny.

I've attached some photos of my set up.

Edit: forgot to add that the lethargic one atm is just sleep everywhere she goes and can barely keep her eyes open.

 

[UnShelled]

A little plain yogurt can sometimes help with runny poop. It can be mixed with some mashed hard boiled egg yolk for energy. If the baby won’t eat you can add water to make soup and dip the baby’s beak in the mixture. You can also try putting a glob of yogurt on your finger and set it against the tip of the beak.
I would not feed uncooked egg to a chicken.

I see that the brooder is the suggested temperature, but are the babies huddled under the heat lamp? If they are, they may be cold. You could try turning the temperature up a little bit- but if you do this check very often! (At least 10 mins) if you see their beaks open turn it down again.

Best of luck! I hope they perk up soon!