Why do my dogs kept fighting?

Okay so I have anpuggle and a chawinner. I have had the pig for 1yar 6 months and she is 1y 9m old. The chawinner is 3 years old and I've ha her since last year October. They just recently started fighting at night in bed and sometimes, occasionally during the day. My partner says it's because they both want my attention and think of me as there mom. Is that possible? Could there be anothere reason? I am thinkin of getting mussels for them. They have just started fight and it now going in 2 moths and almost every morning. Any ideas???