Having been bitten by a rat snake out the back of our Thai house, I might have erred on the side of caution and released only 2 to the garden and the other 4 somewhere far away from the house. They ARE wonderful for keeping rodents down but despite being labelled as "harmless", the bites are very painful! My foot was 3 times its normal size and deep purple coloured for about 10 days. Cobras in the roof cavity I have no problem with, and they're more efficient hunters than ratsnakes. LOL.

Balance is everything. Get a cat or 3 to keep the baby snake population from exploding. :)