Rooster's comb turned dark purple and his tail's lowered

[Laan]

Hello,
We got a rooster and a hen for a birthday gift in June. They're around 5 months old. The rooster started humping the hen and after few weeks she got really injured, so we separated them, so the hen could get better. They've been seperated for a week now (with a see through fence).
Today we've noticed that the rooster's comb turned dark purple and his tail has lowered (it is a really worrying sight). He's not signing every few hours as he used to and in the morning he was more quiet when he sang and it sounded like he has a bad voice.
Is he just stressed because he was seperated (however the color changed over the night) or is this something serious and we should be concerned?

I don't know if it's important, but the temperature is getting lower outside. They have a coop, but are free to walk all around the house and yard, so they're outside all the time.

Can someone please help and explain to me what's wrong with him (we haven't noticed any changes with the hen)?

I attached the photos of how he looked before and how he looks now.

 

[azygous]

Are these your only chickens? I hope so because it's possible these two are carrying the leucosis virus. I have it in my flock, and it's probably there because I got two free chickens when I wanted to start a flock.

The virus is passed from a hen to embryos in the egg. Your chickens may have been hatched with the disease. The virus will cause tumors on the organs, leading to pulmonary issues. If this cockerel dies, you would be wise to have cause of death confirmed so you will be informed before you decide on expanding your flock.

That said, there is another possibility. Look inside his mouth for lesions that may be blocking his airway. If your see buildup of sticky plaque, he has a respiratory disease. Either way, he's a sick boy. The leucosis isn't treatable, but the respiratory disease is, although it could recur after it's treated.

 

[Eggcessive]

What breed are the chickens? It is always hard to know an exact cause for illness without testing by a vet, but he may have heart failure, or some other serious illness. If you should lose him, you can have his body necropsied by your state vet to look for an illness or cause. The body should be kept cold but not frozen. Here is a link to find your state vet contact info:
https://www.metzerfarms.com/PoultryLabs.cfm

In the meantime, make sure that he is taking water, and you can add some sugar or electrolytes. Keep him warm in case he is having trouble keeping up his body temp. Will he eat for you? Scrambled egg, feed mixed with a little water, or tuna are some things that he might eat.

 

[Laan]

Are these your only chickens? I hope so because it's possible these two are carrying the leucosis virus. I have it in my flock, and it's probably there because I got two free chickens when I wanted to start a flock.

The virus is passed from a hen to embryos in the egg. Your chickens may have been hatched with the disease. The virus will cause tumors on the organs, leading to pulmonary issues. If this cockerel dies, you would be wise to have cause of death confirmed so you will be informed before you decide on expanding your flock.

That said, there is another possibility. Look inside his mouth for lesions that may be blocking his airway. If your see buildup of sticky plaque, he has a respiratory disease. Either way, he's a sick boy. The leucosis isn't treatable, but the respiratory disease is, although it could recur after it's treated.

Yes they're the only ones we have. We haven't thought of expanding the flock, because we didn't expect to get them in the first place.
That's terrible, I really hoped the replies would tell me I'm overreacting. We'll try to find a vet that'll treat him. Thank you for the reply, now we know we have to take some wuick actions.

Ps since the hen is alright (at least isn't showing any signs), are her eggs safe to eat? We've been eating them so far..

 

[Laan]

What breed are the chickens? It is always hard to know an exact cause for illness without testing by a vet, but he may have heart failure, or some other serious illness. If you should lose him, you can have his body necropsied by your state vet to look for an illness or cause. The body should be kept cold but not frozen. Here is a link to find your state vet contact info:
https://www.metzerfarms.com/PoultryLabs.cfm

In the meantime, make sure that he is taking water, and you can add some sugar or electrolytes. Keep him warm in case he is having trouble keeping up his body temp. Will he eat for you? Scrambled egg, feed mixed with a little water, or tuna are some things that he might eat.

Unfortunately, I'm not sure about the breed. Google says it's a russian white chicken. We're total amateurs about chickens, because we've never expected or intended having them. They were just a gift for "fun", but we didn't have a heart to take them to the farm where they'd get slaughtered, so we decided to keep them.
He didn't have much appetite today. Thank you for the information, we'll find a vet that'll treat him.
Thank you for the link, but it's for American countires and I'm from Europe. But the important thing is I know we have to do something soon. Thank you.

 

[azygous]

The eggs are safe to eat in any case.