(Chris's PoV)
When I reach Silver Rank, I intend to bond with a new pet that has yet to hatch. It was because, I believe, that the bond that forms after binding with a beast would be greater with an unhatched beast than with a grown adult beast.
Though the time and resources needed to feed and train her would cost me more than it would be compared to getting some wild beast to submit to me or buying a new beast from the market, I believe that it would be worth the cost and effort.
For a beast tamer, the beast's loyalty is more important than anything.
The more they acknowledge you as their family, the better the chances of having a high level of loyalty towards you.
The loyalty of a beast to its tamer matters the most.
This was because, without loyalty, if they sense that they are fighting a losing battle and that their life is in danger, they can abandon the tamer.