Should I tip my dog's boarding kennel?

The kennel where my wife and I board our dog is fairly expensive, but when we pay for boarding the credit card receipt has a line for leaving a tip, like at a restaurant. The kennel also provides grooming services, and the tip line could just be for that. But I’m wondering if I should be tipping the kennel when we board the dog. Anyone know the etiquette on this sort of thing?

Thanks.