She's mostly used to trail and when she is ridden at a canter, mom tends to just go with whatever lead the horse picks up. Seems to the BO like since she only canters on the right lead she may lack the correct muscle to pick up the left lead.
I did some lateral side passes and also trying to push her hip over and sure enough she cannot cross her back legs over when pushing her towards the right. Without being able to push the hip to the inside (aka right) it's hard to really expect a correct left lead.
Anyone have any exercises that could help?