If u want 1 a bit earlier u can actually trade metall or whatever the others want for a fertilized rex egg. Its ideal temperature is between 32-34 degrees. If u have no chance to get a kairuku, a dimetrodon or some air conditioners u can go to an area woth the required temperature (press h to see the temperature). The egg doesnt lose the hatch progress and if the temperature isnt good anymore u can put it in your inventory and it wont lose health. After i hatched u have to feed it by hand untill its grown to 10% (if u go to its inventory u can see how much it will be able to carry when its fully grown and how much it can carry f. e. if it will be able to hold 350 weight its grown to 10% when it can carry a weight of 35). After that it can just eat out of the feeding trough. After 4 days u got yourself a rex (u have to refill the feeding trough regulary since freshies starve fast and meat doesnt last very long). U can also do that with a giga but it takes almost 2 weeks.....

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