With certain animals, why are there so many females and so little males?

Question

For example, chickens. Tons of chickens running around laying lots of eggs and not so many roosters. It seems that this phenomenon is confined to animals that produce yummy eats for all of us, so what, if any method is used to control the sex of said animals? Cows too. All these dairy cows giving milk. Where are their male counterparts?

Answer 1

Why no roosters? Chickens don't have equal numbers of male and female babies. The hens have the ability to affect sex ratios based on what the environment looks like.
http://www.news.cornell.edu/stories/May05/birds.gender.ssl.html
As a bonus, farmers kill many young roosters because they're unnecessary.

As for bulls versus cows? Bulls are often used as breeding stock or meat. So they get slaughtered more, and thus, there are less of them.

EDIT: Serena, Birds don't have the same sex chromosomes as people. Instead of XY, they are WZ. Two Z chromosomes make a male, and WZ makes a female.

Anyway, in mammals, the sex ratio of the offspring, right after birth, is basically 50/50.

Answer 2

We humans select for female chickens. Pretty simple, the female lays eggs and can be consumed. That makes her the most important. The male is around just to be something that transfers male genes. Same goes for cows. Why waste a lots of feed and energy on a single purpose animal like a bull. Besides, once male cattle become sexually mature, undesirable effects occur within the muscle. This can make the meat less desirable by the consumer, the human one.

There is one good example in nature. The ruby throated hummingbird. The males are about half the size of the females and are dominated, even bullied, by them. The male survives only because it has the male genes necessary for successful reproduction.

Answer 3

In a farm situation they are culled and used for meat purposes. On a farm, cows are necessary to give milk and to raise a calf which takes a long time and a cow can only have one calf at a time. On the other hand, one bull can inseminate many cows and if AI is used, there is not much need for more than one bull (larger farms may use stored semen from a bull not owned by the ranch so no bull is necessary). So those bulls are castrated and raised for meat or sold to other farmers who are raising beef for the dinner table. Same thing with chickens. In addition, keeping more than one intact male animal on the farm can be problematic and land-consuming since males housed together will often fight. This means they must be separated on different sections of land. Since land is often at a premium, this is wasteful especially since having more than one intact male is rarely necessary.
This is not confined to animals on the farm. Males tend to be the ones using energy to claim territory, attract mates and keep them away from other males. One male in many cases can impregnate many females and if he has no other parental role, he can go on to other groups to fertilize those females if there is a lack of males in the population. Thus males are expendible. Females are often in the position of raising or caring for young for at least some period of time and so are less expendible to ensure the survival of the species.

Answer 4

You don't seem to have any knowledge of genetics, do you?If you had, you'd know that male are always as many as the female and if there are any differances it's for 0.5%... Insignificant.
It's OK. If you have lived in the countryside, you'd know that your grandpa kills the a rooster when you want to have chicken, because chickens produce eggs, and you need 1 rooster for like 10 chickens, not more. And 1 bull for 50 cows. Males are only used for reproduction... Why to keep more male individuals when they are more likely just to fight and harm each other than give milk?

Answer 5

It is not a natural event. It is a choice by farmers.

When chicks are young they eventually reach a stage where they can be accurately sexed. They are then categorized as female (keep them all for egg production) or male (keep a few for breeding and fatten the rest for meat production.)

Same situation with cows. They are milk or meat sources from the day they are recognizable.

Answer 6

It only takes one male to make dozens and dozens of females pregnant at the same time. If the pregnancy to birth and recovery process happened faster than the "recharge time" of male sex operation abilities i'm sure there would be a lot more males to insure constant expansion of the species.

Answer 7

particularly dissimilar animals... observed hyena - the female is in fee of the gang tarantulas and different spiders - they are plenty larger than adult males, and could usually kill them till now, for the period of or after mating alot of bugs including mantis - they are larger/chunkier than the adult males and could additionally usually kill them mosquitos - the female is the sole one that beverages blood bees/wasps - the adult males purely objective is to reproduce - another bee - drone, queen worker and so on is lady. women folk of dissimilar animals are greater deadly than the adult males, because of the fact the girls folk stay to guard the greater youthful, for this reason making them greater protective and aggressive - bears, some snakes (rattlers and so on), crocodillians, birds (despite if the male of a few species additionally maintains to be to assist), caninies, pussycats, rodents and so on and so on i wouldnt count quantity lion in spite of the undeniable fact that - as despite if the girls folk do the looking, the male continues to be in fee. he gets the 1st chew, chooses who he breeds with and does all the battling. :)

Answer 8

in many species were the male does not help bring up the young, there are more females because it takes a while for the female to raise the young through pregnancy while a male can impregnate as many females as possible maintaining the species.

Answer 9

Well, humans have XX and XY chromosomes. XX is female and XY is male. Since all females and all males have an X and only males have a Y, it's much more common to have two Xs, thus making a female, which makes females more common.

Answer 10

They are killed by us humans. For the chickens I know they do that as soon as the chicks are born, they separate them immediately and kill all the males