Okay, so I forget if the discussion of Polish chickens being a fragile breed was spoken about in this thread, or the other Polish thread, so I am going to report here.
I randomly picked up another batch of Polish chicks (8) that are now about 3 weeks or so old. No losses. I was supposed to have had WCB and SL but it appears as though I have 1 WCW, 1 WCBlue, 1 SL, and 5 WCB's. I started them on medicated starter, only electrolytes in their waterer the first few days after pickup, and nutridrench their first feeding. I fed a wet down starter "mash" while they were inside. I had a runt I specifically picked just to see if it would make it rather than be left to whoever purchased it from the feed store. They are now on un-wet crumbles. They went outside after 1 week for play sessions, had access to chick grit, and are now living in a grow out section of the coop since 2 weeks old. They get a nightlight at night because we've been having unusually chilly evenings, and it is turned off during the day. They have been moved to non-medicated chick starter and I have Corid on hand, just in case. Last week they got a bunch of crickets with the rest of the crew when I stopped by the feed store. I have been sprinkling little bits of corn-free bird seed that I toss to the girls in the morning.
So far, they are doing great. My previous batch of BL and RCR are doing fabulous. No issues. The roosters, Captain and Tennille, are beginning to crow as of a few days ago and nobody is laying just yet. Still too young, but hopefully soon.
Anyway, pretty sure all of my stock is hatchery, except half of my silkies which I know are local breeder eggs. Other than making sure the babies in the grow out are safe, secure, and have a nightlight when it it a bit chilly, I don't do anything special. I just let them frolic and grow.

Pretty soon they wont need a nightlight any more.