I think any system that support growth and a fair playing field for all is a great idea. We need to look after all players equally, as the true aim of the game is to have fun and make new friends.
I think van Loon pigeons has a lot of right in his post. Maintaining the gielda with similar levels would be a real step towards equalizing opportunities.
I agree with the post ... another possibility for balance, would be to file (for example 6 birds) the number of purchases with coins, so everyone would have access to these pigeons of superior quality