Is this English slang?

[Raymott]

"to have bats in the belfry"= russian proverb " to have a mush in your head."

"I did not mess in the head, I have a wide outlook."
You must have some interesting and rather challenging conversations.
However, with the additional information, your correspondent probably means, "I'm not messed up in the head. My outlook is quite clear."

[skotopes]

Thank you very much Raymott! You are helped me.