(Rainbow Bourke) Parakeet with dirty butt--causes?

[Skye'sDucks]

I may have to find a parakeet forum to post this, but I've had so much help for other animals on BYC, so.

I have an older male Rainbow Bourke Parakeet, we got him from a breeder years ago and his cage has been kept the same for the longest time. The last time we switched up his perches was weeks ago. No new changes in the house, havent moved, theres no reason for this to be because of stress.

Yet a little while ago I noticed his butt was a little dirty, but we just kept clean bath water in his cage and waited to see if it would go away.

Finally got to cleaning him up today, and I've noticed not only was his butt dirty around the vent, but he also had a bald patch around it/slightly up on his belly. It looks dry and a little flaky. I've attached pictures.

Quigley, the bird, is as normal as ever. Eating, drinking, bathing, no differences in him at all.
Before telling me to ship him off to the vet, I'd rather do my research first and figure out what might be the cause of this, and if it's something I may be able to treat at home.

I tried doing some research and I'll keep looking while waiting for answers here.
Thanks!

After we cleaned him up

You can see some of the bald spot here. I did clip away some feathers that were caked with poop and weren't cleaning off, but nothing around the bald spot. Only around the vent.

 

[Parront]

What is the temperature where you live? Hot weather can stress them. He could have plucked the poopie feathers himself trying to clean?

 

[Skye'sDucks]

I live in Florida, so we get regular 90 degree weather with 100 feel like temperatures. We keep our house at 78 degrees and its usually pretty cool in here. He's not next to a window, either. He's live in the same spot, here in the same house in FL, since we got him, so I don't know why that would suddenly affect him, unless age has a role to play in that.

I tried to let him clean himself, but he remained dirty for at least a week. I decided to step in and he did a good job cleaning up the stains and the rest of it by himself. I'm going to monitor him to make sure it keeps clean.

 

[Parront]

I live in Florida, so we get regular 90 degree weather with 100 feel like temperatures. We keep our house at 78 degrees and its usually pretty cool in here. He's not next to a window, either. He's live in the same spot, here in the same house in FL, since we got him, so I don't know why that would suddenly affect him, unless age has a role to play in that.

I tried to let him clean himself, but he remained dirty for at least a week. I decided to step in and he did a good job cleaning up the stains and the rest of it by himself. I'm going to monitor him to make sure it keeps clean.

I had an older cockatiel that regurgitated his food the last 2 years of his life. Maybe some different food might help your guy? I fed mine some hard boiled egg yolk 1-2x's a week when I saw he was having trouble holding his food down.