We lost one, think this is why?

[whosthisbroad]

We picked up our 6wk old EEs yesterday morning. They all seemed lethargic after an overnight drive from mypetchicken to our post office. They all found their food and water ok, and as night fell I realized they weren't going to find their way into the coop. I scooped them up one by one and put them into the coop. I came out an hour later to check on them, and one of the ladies had found her way back out, and was huddled down under the ladder. I put her back into the coop. I thought it would be too dark now for her to try that again, so I didn't check on them again until this morning.
My husband found one of our chickens feet up, head down between the planks, obviously passed away. Do you think this is a design flaw, and a weird accident? My husband is going to pick up a piece of wood to put over it to be safe. But I wonder, as this was the most noticeably lethargic chick, was she trying to separate herself because she knew it was coming? Or maybe she ventured out for food and a drink and fell between the boards and couldn't get out and froze. We are all devastated.

 

[whosthisbroad]

I'm adding a photo of where the platform is compared to the ladder for reference.

 

[Pork Pie]

I'd put it down to an accident. Chickens cannot see in the dark, so maybe it got so dark that it could not navigate the platform.

You may be best advised keeping the chicks in the coop for 2-3 days (with food and water) so that they associate the coop with safety, and a place to retreat to when darkness begins to fall. After that, open the coop door and put food and water in the run - they should happily venture out of the coop, and hopefully return to the coop on an evening. You can hang a flashlight in the coop on an evening and this should help them migrate to the coop if they are little slow to work it out.

 

[azygous]

CT has a good suggestion, but don't expect chicks to view the coop when outside in the run the same as they view it from inside the coop. Their thought processes haven't matured to that extent yet.

You need to teach chicks to go inside the coop when night comes.

Why don't you do us all a big favor and fill in your profile info so we know what region you live in. Is it freezing still at night where you live? Your chicks, while feathered, may not be cold hardened and may need to be acclimatized to your regional climate.