I have an eight month old male Cairn terrier named Zipper. Two days ago we got a 7 week old Cairn mix female. How would I know if this will work out?Zipper doesn't seem to hate her but wouldn't leave her alone. He mouths her but his tail is wagging. So we whine up keeping her in the crate alot. She only weights 2# he weights 10. Sorry if this is in the wrong forum.