It's not something I would do personally, as I think there is better options than close inbreeding but one of my mates coursing bred dogs lined one of his daughters last year full litter were fine, I took one on and he was very late to mature and still very puppyish now at 16 month but he got a great attitude towards work, he shaping up very well for this season and is a much stronger dog than both his sire and dam imo both him and one of his siblings done well last year as puppy's ?