Why would tiny chiks be pooping pure water??? Should I be concerned?

Okay so I have never seen this before and online research is not helping as all I can find is chickens get watery poop when it is hot, but they are not hot and this is not just watery poop, they are also passing pure water.

I got some feed store chicks yesterday day, I have only had them since 10am Friday, I am unsure of the age but they only have an inch of wing feathers. Of them I have yet to see either white crested black polish produce a normal poop, I have not witnessed many poops but so far what I have seen comes out is either watery and very undigested (it looks and feels like wet food) or what seems to be pure water.

They act fine, they eat, they run around, they went berserk for scrambled eggs, one does whine a bit. I have them on medicated chick start and there is "chick boost" in the water. I do not have chick grit but just an hour ago I sprinkled in the smallest bits of pigeon grit I could pick out of my bag in hopes that grit helps with the undigested food issue, I did not see them swallow any (pieces may be too big)

So.... should I be concerned about their poops? I have no idea what is going on.

I would give them some probiotics or a tiny bit of yogurt mixed with a little egg and chick crumbles into a mush with water. I Was at a feed store last week that had empty brooders, and I noticed that they had soiled bedding from previous chicks. I was hoping that new chicks weren't going in there later that day. Coccidosis usually is not a problem until chicks are over 2 weeks old, and usually due to being exposed to other droppings or cocci in large amounts in the soil.
I would check your brooder temperature to make sure with a thermometer that it is 85-90 F. Drinking more water can cause watery poo. If any look weak or lethargic, then get some Corid in case of coccidiosis. It won't harm them, even if they don't have it.

would you say the issue here is either coccidosis or a non-infectious issue of the digestive tract? I have more chicks I hatched myself that I was going to add to the brooder today, I planned this hatch to coincide with the feed store order to make life easier raising them all as one unit, but I do not want to place them together if it risks my hatchlings (but it really complicates life to keep them separate)

They may be alright, but if you have any doubts, don't do it. May be keep them separate for a day or two, to make sure the feed store chicks are alert and active, eating and drinking. Sick chicks should look ill, puffed up and standing around not eating. How many chicks of each are you talking about?

I purchased 2 white crested black polish, 8 frizzled cochins, and an Old English Friday morning. I hatched 11 silkies Friday afternoon through Saturday morning.

It seems to only be the polish with a problem.

At most the only "sign" of illness I see (aside from poos) is the one polish tends to whine a bit, and I say "sign" because it still acts fine, but of it's not digesting properly then it probably feels hungry all the time is why it whines. One frizzle had a pasty butt when I got it (was the only one that color so I took the risk) but it was not severe and cleared up by Saturday evening.

I found my bird grit which I gave them only to take it away minutes later as I read it has calcium carbonate in it, they all ate some but it was not in there for long so hopefully no harm done (I really hope no harm done!!! ahhh!). I just cleaned some decomposed granite from the side yard and now have it soaking in boiling water, I am going to offer that to them and then do another meal of scrambled eggs and hope for proper poops.

I put 3 pretzel salt sized pieces of grit in the whining chicks mouth as it was not eating any, and I just gave them scrambled eggs (so much mayhem lol) so now we wait.