I have an 10 month old Great Dane puppy who was housebroke in under 48 hours and now will only go in our yard. This causes problems, because if we go somewhere for the night, she will hold it until she has an accident - always indoors, even though we will take her out as soon as she signals. I'm at my wits end. I've even planted rocks with her urine on them and her own feces outside, but she will not go outside if it's not our yard. This makes it difficult for her to do everything we want her to be able to do. Please Help!