Whining/whimpering? What is this sound?

[Star428]

My silkie rooster made this sound while snuggling... never heard of a rooster making whiney noises? Is there a name for this sound or is it just a silkie rooster attempt at purring?

 

[kcan2]

Although I have never heard it before, it does sound like a relaxed/contentment sound. Best video award for being adorable!