Chicken Math To Consider For Small Additions

[Snowbelt]

Let's say you are looking to add to your flock, but for whatever reason you need or want to purchase or hatch straight run chicks. Wouldn't it be nice to know what your chances are of getting a certain number of hens or roosters in small purchases? Well, the (chicken) math is both straightforward and predictable. For example, assume your chances of getting a straight-run rooster (R) or hen (H) for any individual chick is 50%. And you are considering purchasing three chicks. There are 8 possible combinations of hens and roosters, as follows:
HHH
HHR
HRH
RHH
HRR
RHR
RRH
RRR
Note that your probability of getting all hens, or all roosters, is only 1 in 8, or 12.5%. And your probability of getting exactly two hens (or two exactly roosters) is 3 in 8, or 37.5%. That's the same probability of getting exactly on hen (or one exactly one rooster). If you wanted both hens and roosters, your chances when purchasing just three chicks is 6 in 8, or 75%. If you wanted hens, you have a 7 in 8 chance of getting at least one hen, or 87.5%.

You can do the same chicken math for a purchase of four straight-fun chicks, which gives you the following probabilities:
A 6.25% probability of getting four hens (or roosters)
A 31.25% chance of getting at least three hens (or roosters)
A 68.75% chance of getting at least two hens (or roosters)
A 93.75% chance of getting at least one hen (or rooster)
Only a 6.25% chance of getting all roosters

Hopefully some will find this useful in their decision-making on future flock additions.