How to get a puppy to use yard at my daycare when at home uses only pads?

Good luck! That is worst possible scenario. If a dog hasn't been trained to go outside, then you would have to start from scratch and housebreak the dog. Do you really want to do that? Besides, there's no guarantee it will stick since the dog may not be able to differentiate between his home environment and yours. i don't accept puppy pad trained dogs and it is stated in my profile (I think). Puppy pad trained dogs will use whatever looks like a pad indoors (throw rugs) or just go anywhere if they can't find a pad. If you want to keep the customer, all you can do is put down pads. Attempting to train that dog may be futile.