Each year, Parelli trains over 400 horses per year, using highly trained instructors who treat the horses with the most respect possible. Parelli's training methods are some of the most advanced in the world.
No certain age. I know a 6 year old who can train them.
80,000,000.000
Two to three.
Too many.
50,000 horses die each year because of abuse and abandoning by the owners.
Many horses are saved from slaughter everyday, however just as many, if not more are not saved. There are many ways to help keep horses from being slaughtered, you can Google horse slaughter prevention and find many useful websites.
The number ranges but about 20 each year
3 a year
It is estimated that between 700 and 800 horses are injured or die from animal abuse each year. Many of these are race horses that are injured on the track. The number of animal abuse cases involving horses have went down since the closure of all US-based horse slaughterhouses.
29 thousand
163 this year
A total number per year is hard to come by as there really is no set number for horses retiring from racing per year. Some years more horses will retire due to various reasons, while another year fewer horses will retire.