We all are aware that the environment of domesticated horses and wild or free-roaming horses are not alike. Domesticated horses and wild or free-roaming horses also spend their time and energy differently.
It is important to realise that the behavioural patterns associated with our domestic horses are built upon the behaviours provided by millions of years in the wild and many of these behaviours cannot simply be wiped-out by selective breeding.
There are many features that cannot be changed even in captivity! For example, as highlighted in the previous H&P article (You are what you eat; evolution of horse dentition), the herbivorous nature of horses was determined early-on, and the horse’s systems, both physically and behaviourally were refined by their diet.