I returned from a Massachusetts visit with a Praying Mantis egg case and instructions to keep it in the fridge till the 15th of April, then out to room temperature and wait till some time mid May for the little ones to arrive,
About 5 AM I went to look at the container, and
they were streaming out of the egg case by the dozens.
I quickly dressed, took them over to the gardens at the church around the corner, and released them over the whole area into the verdant green.
There were at least a hundred, maybe more by the time I got there They have plenty of room to mature and live a full summer eating other insects.
I use no pesticides so they are safe in that way, and what the birds don't get will lay new egg cases when the time is right.
It's possible we will have them for many seasons to come.