Help! 1 week old chicks suddenly acting lethargic (all 12 of them)

[nuthatched]

Could the lid be leaching fumes when warm?
Medicated feed won't do anything if they have coccidiosis, but corrid will.
If they haven't been exposed outside, they likely don't have coccidiosis.

 

[rosemarythyme]

If you have similar issues in the future get a temperature reading in your hottest and coolest areas and that will help with assessing if heat is an issue.

Hard to tell if the waterer has regular horizontal nipples as those aren't meant to be used with young chicks. Having a more open waterer (or vertical nipples) might help especially if you think they might be hot, which would cause them to increase their water intake as well.