Conures fighting

Question
Hi, I have a 4 month old green-cheek conure, and a 4 month old Sun conure. Both were raised in the same cage by the same woman. I purchased them both together and they have been living together happily in a relatively big cage. They cuddle with each other, clean each other and have been getting along fine since I got them about a month ago. As of yesterday, the green-cheek has been chasing the sun around the cage, screaming and biting his feet and wings. The sun is scared of him and screams back. If left alone, they will scream back and forth and the sun will lay on his back while kicking the green-cheek. It's clear they're not playing anymore. I have separated them, do you have any ideas what might have caused this sudden change in behavior? What should I do about it?

Answer
Sometimes issue's like this develop as birds mature. They begin to become territorial, etc.

If they don't get along, you will just have to keep them separated, or they will end up injuring one another.

You can leave them in separate cages near to each other. They might still even get along outside of the cages when you let them out (Much more space that is not either birds territory).

Also, they will better bond with you if they are in separate cages.

Blessings,
-m