They have pseudo-bones (basically just cartilage with minor mineralisation). These “bones” are nothing like they were like 40 years ago. This cartilage is of co

They have pseudo-bones (basically just cartilage with minor mineralisation). These “bones” are nothing like they were like 40 years ago. This cartilage is of course tough, but try cracking a wishbone of a modern meat chicken - it just bends rather than snaps. Interestingly the growth rate of modern meat chickens is limited to bone mineralisation rate. If you breed a chicken with faster growth rates (which you can do) they end up with broken legs as the bone can’t support the weight of the bird [1]. 1. http://japr.oxfordjournals.org/content/16/1/138.full.pdf http://japr.oxfordjournals.org/content/16/1/138.full.pdf