budgerigars of all different colors.
Even then, you can only reasonably expect to breed budgerigars equal to the average quality of the stud from which you buy.
A wire mesh measuring 1 " x 0.5 " is suitable when keeping budgerigars.
There is also an article, written much earlier, by Ethel Dobie which also appears on this website, describing mottled budgerigars.
Don't expect to go to a top stud and buy budgerigars for pet prices.