Roughly 1,200 of the nation's 6,700 animal shelters and rescue groups -- more than one in five -- identify themselves as no-kill, suggesting they subscribe to the ideal of euthanizing only those creatures suffering from terminal illness or injury or too vicious to live among humans. But no matter how shelters label themselves, their performances and policies are as mixed as a mutt's pedigree, SHNS reporter Lee Bowman has found. The stark reality is that half of the estimated 8 million dogs and cats entering U.S. shelters of all kinds last year were put down. Still, the no-kill movement is making a positive impact.