Whether rack system or display enclosure, both are fine if done correctly. Its just personal preference.
Ball pythons spend 90% of their time in the wild holed up in rodent burrows and termite mounds. Can't imagine any of those spaces are very large. A rack simulates these housing conditions. Big open spaces stress them out if adequate hides and cover are not provided.
Colonizing can be done, but not recommended.
Being too active is a sign of stress. Especially if its during the day. A hiding ball is typical a happy ball, which is why they are poor display animals.
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