They will be fine too work this year around about Sept, October but November, December would be a more realistic time to work them. I would personally try them out for the first few times on very small buries. If you get them running through pipes now they will be used to tight dark spaces and will enter the bury through curiosity and more easily. Don't expect them to be 100% straight away it will take a few trips and a bit of patience but once they get to know that there is potential food down there, there will be no stopping them. One other thing is to get yourself some flea and tick spray