A couple weeks ago I posted and asked fellow BYC'ers to tell me the male/female ratios they experienced in their straight-run hatchery orders. My intent was to gather data to better understand what straight-run really means. I received a lot of data and present below the findings of my analysis. Many thanks to all who commented on their straight-run ratios. First of all, the data consisted of 16 people who ordered a total of 417 straight-run CX from various hatcheries. Of these birds, 152 were male. So, the proportion of males in these orders averaged 36%. So, on average, when you order straight-run CX from a hatchery, you are likely to get approximately one male for every two females. Interestingly, the 6 people who ordered from McMurray averaged 31% male while the 10 people who ordered from other hatcheries averaged 43% male. We can definitively prove, using a binomial test, that these male ratios significantly vary from a 50:50 ratio. So, if you thought straight-run meant having an equal likelihood of getting boys and girls, this little mathematical exercise proves you wrong. However, thanks to the insightful comments of JohnL11935 (@comment#6), BackyardAR (@comment#22), and WinsorWoods (@comment#25), we have an alternative hypothesis for what straight-run means and I think they are right. They posit that straight-run just means unsexed leftovers That is, a hatchery will fulfill its orders for sexed chicks first, then fill orders for straight-run randomly out of what remains. Imagine two buckets into which chicks go at the hatchery: sexed females and sexed males. Once the sexed orders are filled from the two buckets, all the remaining chicks get combined into a bucket from which all straight-run orders are filled. So, if you order straight-run meat birds, for which many people prefer to buy sexed males, the hatchery will first fill those male-only orders, and then fill your straight-run order from what remains, which will be disproportionately female. And the opposite is true for ordering LAYER breeds. If you order straight-run layers, for which almost ALL people prefer to buy sexed females, the hatchery will first fill those female-only orders, and then fill your straight-run order from what remains, which will be disproportionately male. The moral of the story here is if you really care about the male/female ratio of your order, buy them sexed. Otherwise you can expect a roughly 1:2 sex ratio skewed in an undesirable direction. As for me, I will probably continue to buy straight-run CX because I prefer to have them finish out over a period of a few weeks rather than all at once. I like to process in a few batches rather than one marathon session.