We do require PLASTIC QUICK RELEASE DOG COLLAR that is a snap and go which can be easily removed by pinching together the black plastic ends. These collars can be purchased at a pet store or online. Although very popular, buckle collars are dangerous in dog play groups because of the buckle’s pointy edges. We do not keep harnesses on during group play nor when boarding. Sweaters are allowed in group play. It does get chilly during our winters and we like everyone to stay cozy warm.