It doesn't matter what you chose, ratio will be 50% after one generation regardless (unless aliens do something really nasty like gender-related abortions).

If this is not the answer You're looking for please specify better.

#Clarification For all vertebrates reproductive balance is 50/50, with no exceptions.

Chicks are born evenly matched (so many would-be-rooters and the same number, on average, would-be-hens). Reason why you have "many hens, one rooster" is because we kill (and sell as meat) all males. In the wild males use several techniques to scare away or simply kill off competition. Exception is when it's needed a combined effort to give next generation better chance to survive; there you have stable couples (family, if you want).

In our species spermatozoa (from males) are responsible for sex of newborn and our testicles produce exactly the same number of Y-bearing (male) spermatozoa as X-bearing(female) ones. Gametogenesis (Meiosis) guarantees that.

If "aliens" want to "increase throughput" have a few options:

• Somehow kill Y-bearing spermatozoa before insemination (not easy task as there are billions of them).
• Provoke abortion of male embryos (easy and well tested, usually on the reverse sex, as happened recently in China).
• Sell males as slaves or raw meat (I would think such an advanced race doesn't need human slaves, but we could be a real delicacy to them, who knows?).
• Have males to fight to death until the ratio is "right" (they would make billions of credits broadcasting live in galaxy-vision!).

All gruesome alternatives, but perfectly viable, from alien viewpoint.

Al they have to do to ensure balanced distribution on arrival is to stop interfering about 50 years before arrival.

It doesn't matter what you chose, ratio will be 50% after one generation regardless (unless aliens do something really nasty like gender-related abortions).

If this is not the answer You're looking for please specify better.

Clarification

For all vertebrates reproductive balance is 50/50, with no exceptions.

Chicks are born evenly matched (so many would-be-rooters and the same number, on average, would-be-hens). Reason why you have "many hens, one rooster" is because we kill (and sell as meat) all males. In the wild males use several techniques to scare away or simply kill off competition. Exception is when it's needed a combined effort to give next generation better chance to survive; there you have stable couples (family, if you want).

In our species spermatozoa (from males) are responsible for sex of newborn and our testicles produce exactly the same number of Y-bearing (male) spermatozoa as X-bearing(female) ones. Gametogenesis (Meiosis) guarantees that.

If "aliens" want to "increase throughput" have a few options:

• Somehow kill Y-bearing spermatozoa before insemination (not easy task as there are billions of them).
• Provoke abortion of male embryos (easy and well tested, usually on the reverse sex, as happened recently in China).
• Sell males as slaves or raw meat (I would think such an advanced race doesn't need human slaves, but we could be a real delicacy to them, who knows?).
• Have males to fight to death until the ratio is "right" (they would make billions of credits broadcasting live in galaxy-vision!).

All gruesome alternatives, but perfectly viable, from alien viewpoint.

Al they have to do to ensure balanced distribution on arrival is to stop interfering about 50 years before arrival.

It doesn't matter what you chose, ratio will be 50% after one generation regardless (unless aliens do something really nasty like gender-related abortions).

If this is not the answer You're looking for please specify better.

It doesn't matter what you chose, ratio will be 50% after one generation regardless (unless aliens do something really nasty like gender-related abortions).

If this is not the answer You're looking for please specify better.

#Clarification For all vertebrates reproductive balance is 50/50, with no exceptions.

Chicks are born evenly matched (so many would-be-rooters and the same number, on average, would-be-hens). Reason why you have "many hens, one rooster" is because we kill (and sell as meat) all males. In the wild males use several techniques to scare away or simply kill off competition. Exception is when it's needed a combined effort to give next generation better chance to survive; there you have stable couples (family, if you want).

In our species spermatozoa (from males) are responsible for sex of newborn and our testicles produce exactly the same number of Y-bearing (male) spermatozoa as X-bearing(female) ones. Gametogenesis (Meiosis) guarantees that.

If "aliens" want to "increase throughput" have a few options:

• Somehow kill Y-bearing spermatozoa before insemination (not easy task as there are billions of them).
• Provoke abortion of male embryos (easy and well tested, usually on the reverse sex, as happened recently in China).
• Sell males as slaves or raw meat (I would think such an advanced race doesn't need human slaves, but we could be a real delicacy to them, who knows?).
• Have males to fight to death until the ratio is "right" (they would make billions of credits broadcasting live in galaxy-vision!).

All gruesome alternatives, but perfectly viable, from alien viewpoint.

Al they have to do to ensure balanced distribution on arrival is to stop interfering about 50 years before arrival.