If you mate the heterozygous anerythristic boas, you can expect 1/4 of the babies to be anerythristic and 3/4 of the babies to look normal. What you actually get probably will not match those fractions exactly, but it is likely to be close. Many, but not all, of the normal-looking babies will be heterozygous anerythristic. You can sell all of the normal babies as 66% probability heterozygous anerythristics.

I would sell most of these babies and buy relatively unrelated stock for further breeding.

Good luck.

Paul Hollander