AMARILLO — A miniature horse given to a boy with brain cancer by the Make-A-Wish Foundation was killed by a pair of pit bulls who were found roaming in his yard, authorities said. The 31-inch tall horse, Anniversary, was donated by the foundation to 3-year-old Christian Vasquez in late August. Christian, who was diagnosed in January with a malignant form of brain cancer, received a pull cart, a blanket, a halter and a bridle set from the foundation on Saturday, said Jelaine Workman, executive director for the foundation's Amarillo chapter. Two days later, Anniversary was found dead on his property...