Greetings Chickenlover9090,
Hm-m-m, I am thinking this could be heat related. Silkies are supposed to do OK in heat. But, every chicken is an individual...
How old are your chickens? Since it is Summer in Australia, do they have adequate shade and cold water? Chickens will not drink warm water, so they will get dehydrated very fast in high heat.
When chickens are hot, they open their wings away from the body, and they pant to cool down. They will also, drink a lot of water, then poop out watery poops. This is how they deal with the heat. But, chickens can die very easily in extreme heat if they are not cared for properly.
If you feel this is a possibility, let's start with that.
If his eyes are closing and he seems lethargic, he may be experiencing heat exhaustion. The clock is ticking...you will have to judge if this scenario is possibly the problem.
Fill a dish tub with cool water, then, place the rooster into the water to cool him down. Let him sit in the water for about 5 minutes. If, he wants out that is OK too. Towel dry him, and let him air dry. Offer him some cold watermelon or other melon variety. Chickens tend to eat less in high heat also. So offer cool treats, put ice in the water or frozen berries or grapes.
In extreme heat of 102-103 degrees or higher, you will need to put some electrolytes into the water. Make fresh each day. Use for 6 hours then replace with fresh water, for four days.
It gets really hot here in Southern Calif, USA. Two of my chickens are very heat sensitive, due to their breed. I have trees near the coop and run, but I also set up shade tarps facing the southern sky where the sun's rays are hottest. And, I operate simple box fans and an inexpensive misting system (for adult chickens) to provide a cool zone, where they can go if they are overheating. Also, if you position some tubs of water in front of the box fans, the constant air movement will keep the water cold. Use caution with tubs of water, if you have chicks, as they can drown!
Here is a simple recipe for home made electrolytes:
1 cup water
2 teaspoons Sugar
1/8 teaspoon Salt
1/8 teaspoon Baking Soda
Combine all ingredients, mix one cup per gallon of water.
Sometimes a chicken gets severe heat exhaustion, and may require that you bring them into the house if it is cooler there. It can take a few days for the chicken to fully recover.
So, go over this information and decide what you need to do for your boy.
These are my thoughts for your rooster. I hope they are helpful.
If you notice any other symptoms that don't fit heat exhaustion, please post them.
Other members will offer advice, please consider them too.
God Bless.
