Young Chicks Dying Suddenly

[WhiteValleyChick]

I got 10 three week old RIR pullets from a bin at my local feed store. We put them in a pen with existing chicks of similar size (and 2 that were a *little larger). We had them for just under a week. They appeared lively, eating well (non-med feed), lots of fresh water plus a separate bowl with electrolytes.
I watched them every day and they all seemed to mingle fine.
Then one day 5 of them were dead. No warning, no noticeable injuries, great muscle mass for their ages, normal poop, normal crop, overall the chicks looked really good.
All other chicks appear fine, just as these did the day before they died.
We've raised lots of chicks over the years and have never lost this many overnight in one flock before. I'm kind of at a loss.
I know they ate well and I watched them drink countless times so I assumed the 2 biggest chicks didn't keep them from their resources. Do you think they could have been bullied? Trampled? What should I be looking for without a single shred of evidence that they died of illness or infestation?

 

[Wyorp Rock]

I'm sorry for your loss.

How much space do they have? Photos?

How many chicks total in the brooder?

Were they scattered or in a corner or ? Trampling or smothering is a thought.

 

[FBMcrazy8]

I’m sorry. I’m new to raising chickens and I wouldn’t have a clue. I do hope someone on here can help you!

 

[WhiteValleyChick]

I'm sorry for your loss.

How much space do they have? Photos?

How many chicks total in the brooder?

Were they scattered or in a corner or ? Trampling or smothering is a thought.

They're in a 6x6 pen, they're not crowded at all. There were 18 altogether. Seemingly plenty of space and they were normally scattered, exploring/scratching. They have a couple cinder blocks to run around and on top of. One of their waterers is on a block, they frequently get on top of them. They also have a large box to roost in and an open roosting bar.
I took the 2 larger pullets out, I'm going to wait a few days and if I don't lose any more, all I can assume is that they were being picked on. I may add Corid to their water as a preventative, just in case.

 

[Wyorp Rock]

They're in a 6x6 pen, they're not crowded at all. There were 18 altogether. Seemingly plenty of space and they were normally scattered, exploring/scratching. They have a couple cinder blocks to run around and on top of. One of their waterers is on a block, they frequently get on top of them. They also have a large box to roost in and an open roosting bar.
I took the 2 larger pullets out, I'm going to wait a few days and if I don't lose any more, all I can assume is that they were being picked on. I may add Corid to their water as a preventative, just in case.

The Corid won't hurt anything.

Space/pen sounds great. A good possibility the older ones bullied them, chickens aren't always that nice.

Hope you don't suffer anymore losses.

 

[WhiteValleyChick]

The Corid won't hurt anything.

Space/pen sounds great. A good possibility the older ones bullied them, chickens aren't always that nice.

Hope you don't suffer anymore losses.

Since moving the bigger chicks, so far so good..fingers crossed! Thank you!

 

[Madhouse Pullet]

Im so sorry for your loss I hope you found a solution

 

[Wyorp Rock]

Since moving the bigger chicks, so far so good..fingers crossed! Thank you!

Glad things are going good!