Okay, so I assume you're running at about 99.5 temp and about 40ish for humidity, right? So, on day 18 lock 'em down and run the humidity up to the lower 60s. When those chicken eggs hatch get them out as quickly as possible (wait until they're all hatched) and dial that humidity back. Day 25 lock 'em down again with your humidity in the 60s and let's hope those turkey eggs are okay. I did the same thing last year, lost two and saved one.
Good luck