Your post is confusing. It is either crèche reared or parent reared. Parent reared is usually reared in a seclusion aviary by its parents, crèche reared is reared with its siblings by a human.
I don't see the advantages to crèche rearing a Harris hawk as they are so naturally tame and steady.
Even wild caught passage Harris's can scream as they are clever enough to understand who provides their food.
You are better off leaving a parent reared Harris with its parents until around 17 weeks of age. Then gently get its weight down so it's responsive, then get it entered ASAP. So