But as a husband I also have to caution to go slow on this. You haven't told us WHY he objects to your getting more birds. That has everything to do with the matter. WHY does he object? If you know that then perhaps there is a way to mollify him.
Every once in a while my wife will really put her foot down about something. In those cases I try to explore with her what her objections are then do what I can to remedy them. I very seldom will just bull ahead and do it anyway if I know she is really set against it. That only creates hard feelings that WILL express themselves in other areas in other ways.