Petey and Jessica have been bonded for about 2 years now, never had any issues when they were first put together, no chasing, fighting or anything, they had lived side by side with just a piece of wire between them for 6 months I took the wire awy and they just lay down next to each other, now 2 yrs on for some reason they have started the chasing and mounting and a little bit of biting (but not drawing blood) I dont know why they have suddenly started this but as they are not hurting each other i have just left them to it, they only do it every so often, very weird!!!!