Schools - Is it acceptable for a teacher to advice me to send my grade 1 son to another school just?

I'm sorry to say that but maybe you should consider
telling your child to behave. It is definitely not nice
to hear that from a teacher, but what if she is right?
Just don't make any quick choices. Why did she tell
you such thing? Did she have a point which she could
prove? If yes, apologize in behalf of your little one
and punish him. If not, then maybe contact the head
master and tell that this specific teacher is being mean.