Boa Constrictor Questions?

I keep my boas separate. My ball pythons are all separate. They can be housed together if they are about the same size (same breed), but not recommended. My friend had one of his boas attack and kill another boa. During feeding they should be fed separately. I haven't bread snakes do to the time constraints and requirements for breeding. I have 2 boas that are approximately 12feet plus long and way about 45lbs. My ball pythons are nearly 5 feet each and weight mayb 8-10lbs each. And you cannot house them with other animals I.E. frogs and lizards. They will kill them if they feel threatened.