I usually will drop 7 to 10 birds per dog and do our best to hunt em all. They always run back to the Johnny House too fast when I let em fly out. I've started netting them and moving them to a different release area so all 7 or 10 actually "hunt true".
If I'm working the dogs with people who are with me wanting to hunt, I put out more depending on the folks.
So, the high end would be 150- 250 in your example above. That's a lot to keep alive all at once. We break it up and re-stock every 2-3 weeks to limit the loss. It gets expensive since we don't raise the birds.