Help! my JH that pinned every mark last year is running real big on marks. We spent late winter and spring working on PB, WW lining & casting and progressed to cold blinds. While I did some marks during the winter-spring likely not enough. Now I need to get him back on track. Last week at training nite a double thrown into tall grass about 40 yds. He proceeded to take a straight line right past the mark and hunted a 5 acre field. Did the same thing on the memory bird. Needed help to get the marks. This has been the case the last month on at least half of his marks.
What marking drills would get him back on track?