This is, at least for the current experimental & 0.F candidate (and quite a few versions back - including 0.E stable), incorrect. They grow up after 7 days, as the file and testing shows.
After 7 additional days, they also turn into pregnant giant cockroaches.
That’s also incorrect. They hatch once the egg item has “rotten away” (similar to (fertilized) bird eggs) based on the file (and I could verify that they spawn from eggs via testing).
And the third wrong statement…
Both the giant cockroaches and pregnant giant cockroaches “lay” (spawn in) eggs every 7 days, 1 single egg from the giant cockroach and 3 from the pregnant ones.