I am curious to find out how long people keep their Meeroos before releasing them to the wild -

Currently my goal is to let them age out and release them after their last breeding cycle, but this makes for slow progress. I did get impatient and release a few (6) around the forty day mark, but I have not coaxed any new nests yet to replace those numbers.

What is your process, do you let them age out naturally or do you cull after a certain number of nests? Do you rank based on performance?