I thought I read somewhere this summer that sex determination via temp does not occur early on or at the start of the incubation period, which is what I intuitively thought or would have guessed just like you, but rather is dependent on the incubation temperature towards the middle of developement a few weeks before hatching. shrug.
That one in the top right pic sure looks like a "clown" faced male, should be a really nice looker.
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Jeff Benfer
gartersnakemorph.com