I am starting to foster.It seems the above breeds are in most need.i had a king charles foster,last time,and have a Jack russell of my own. So very different breeds. What 'special needs' do these dogs need,and why? For example,greyhounds and the wide collars,and every staffy pic i see,the dog has a harness on. is it because they pull so much? What other traits do i need to know about?