Ok so each place does the hay differently. Your best bet is to call the place that you want to go to and ask them if the hay ride will be Caliac friendly. If they do not know (you might not be the first????) then they can call the farmer that they are getting the hay from or they can provide you with the number. Now this does several things it educates another group of people that we exist and like to have fun too and it also allows you to know if you can safely put your child on the ride. If the farmer has something in the hay that is not Celiac friendly then the place will know next year and hopefully remember that we exist. If you have a blog then you can tell them that you are willing to link to them if they will provide a Celiac friendly hay ride next year and ask them if they will do one first even so that there will be no cross contamination if you have a Celiac group in your community.