Blood or intestine shedding?
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I don't really know what the reason for chicks pooping reddish orangish color poop. But some will poop that and be fine.
Hopefully someone will respond with a better answer than mine.
Week old chicks don't generally suffer from cocci, but the last pic looks like blood. Is there any way to get a sample of their droppings tested at your vet on the AM? How do the chicks act? If you have any doubts, go ahead, and get some Corid to treat for possible coccidiosis. Dosage is 1/2 tsp of Corid powder to a quart of water for 5 days.