We recently acquired a 10 week old female collie puppy. We also have a 12.5 year old neutered male collie. I can't say they are bosem buddies yet. Our old boy is very gentle and has been very tolerant of our rather "pushy" puppy. He will, however, tell her off when pushed.
We have had our puppy for 2 weeks and she has done a wee on our old boy's bed 4 times. Today she went to his bed and started to nip at him to entice him to play. He told her to get lost with a lip curl and she responded by squatting and weeing on his bed!
We are keeping a close eye on her and her toilet training is pretty good for such a young pup. However, she doesn't show the usual "signs" before she urinates on our dog's bed. Any clues as to why she is doing this and how we can stop it?