I used to have Pietrain X weaners, perfect on a saddleback as they came out leaner. I sent mine off always before 6 months understand about mixing the sexes. The only problem we had when like that was they would scrap and sometimes nastily, blood and pigs don't mix. It's amazing how spiteful a pig can be to its siblings, yet when they are all boars, never had this problem (the last 4 were all boars and turned on the sheep and the cattle, but not each other! Enjoyed eating those little blighters at 5 month!)