By HOLLY RAMER STRATHAM, N.H. (AP) — A group of mice is called a nest, but what do you call 1,000 of them in one animal shelter? “Crippling,” said Lisa Dennison, executive director of the New Hampshire Society for the Prevention of Cruelty to Animals, which is scrambling to care for an overwhelming influx of rapidly reproducing rodents. It all started Monday when a man arrived saying he wanted to give up 150 mice.