If you stay with a high percentage SD male retic you could probably keep it in a 4x2 cage. Never really know, sometimes they just grow. My SD gal Phyllis is 13.5 months old and is about 7' already. Some of her siblings from the same clutch are less than 5'. Mine just really thrived and still does. She just moved up to large rats and now a 10 day feeding interval.
Now my male 50% SD ultra ivory Gerald is 12.5 months and between 3.5-4'. Tiny. He was fed more conservatively than Phyllis though. I digress...
I vote you get an SD retic Ziggy! They're a blast. I would like an olive though myself...
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