Personalized Happy Birthday with Dog and Mouse Youth T-Shirt. Dog and Mouse are excited to wish you the happiest of birthdays! Happy Birthday with Dog and Mouse Youth T-Shirt - Kelly Green, perfect for those who love this friendly duo from "Dog and Mouse" by Michelle Nelson-Schmidt. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.