PLZ HELP! Chicks are dying. Cannot find the cause

Hi Everyone.

I am a noob from NZ.
I have started to hatch my own chicks about one year ago.
Before I was hatching 6-12 each week, a brooder holds 30ish chicks in 3 age groups.
Suspend stainless mesh wires with fresh newspaper every day.
Fully insulated dog house, with thermal controlled lights.
Fresh warm water, medic grade feed.
The dying rate was much less than 5%.

Recently I started to hatch 20-30 eggs each week.
In last 3 weeks, I have start to having chicks in my new home made brooder.

Stainless mesh suspend from a pallet. Finding chicks dying, then went back to my old way, having fresh news paper every day, still finding chicks dying, and then added pine shavers on top of newspaper, still can’t stop chick from dying.

One light (bright) on thermal control, one lower voltage light (bright) is constantly on, finding too hot. And chicks dying, now went back to my old way, which have both light on thermal control.

Feeding medic grade chick’s starter all the time.

Feeding AHE (apple cider) added to water, finding chick dying, and now fresh warm water only.

I have kept adding new chicks (3-4 days old) to this brooder, it contains 3 groups ages, (like my old brooder before, just not that many chicks in once), but after more than 5 chicks died, I have separated the brooder into two. But chicks still dies every day.

Dying chick starts with winds down, looks sleepy, eyes closes, heads down, some of them definitely under growth in weight, but bigger chicks dies too. Crossed breed has significantly more %death, than silkie and araucana.

Now the chicks down to 40 ish from 60 ish.

During the meantime, I have to pull out my old brooder, and making smaller brooders instead of the big one, and fully separate chick by group, and isolate problem, hopefully I can identify the root causes.

So far, only thing I could think of is temperature difference in a large brooder (5c difference from under the light to the edge of wall). Where my old one only varies about 2c.

And flys/mosquitos have been found in the new large brooder. Where the old one has none, thanks to small ventilation gap.

I have loaded more photos, any suggestion or comments are welcome and appreciated.

Have you notice any change in poo colore or any discharge from their noses? This could help to find out what the problem is. I normaly put some glucose to my chicks in the water to help those who couldn't eat and the sick hens too. I think that will help keep them alive before you figure out the problem. One spoonfull is enough for two litters of water then you add any other medication. Best of luck.

I would suspect either coccidiosis since you have multiple age chicks, but infection from incubators can also be the problem. You can try medicating your new chicks with a preventative anti-cocci medicine such as Amprollium at several week intervals until they build up a resistance to coccidia in the environment. Make sure that your incubators and brooders are disinfected thoroughly with a 10% chlorine bleach or equivalent disinfectant and dried before hatching new chicks. Clean eggs and healthy parent stock help. Good ventilation in the incubator and brooder and avoiding too hot of temperatures may help. Here are some links about cocci and incubation problems that you may want to read:
http://www.the-chicken-chick.com/2012/12/coccidiosis-what-backyard-chicken.html
http://msucares.com/poultry/reproductions/trouble.html
http://extension.illinois.edu/eggs/res24-14.html

Thanks guys. I think I need do a clean up in the brooder, and separate the chicks by age group. The incubator seems fine. As I had my new chicks in the old brooder for over a week now. All chicks gaining weigh as normal, and no chicks dying. I guess it could only lead a few things, the multiple group ages, treated plywood I used, large area of brooder.

Your welcome. Don't forget to use probiotics for 6-10 weeks from day one.