I would suggest using grain free products. Also no corn!!
Pumpkin based would be good as well as sweet potato.
The thing is, for example, using oatmeal would be good- but I also know two people who have bullies allergic to oats!! Peanut butter- another gummy treat- but recently found out that miss bailey is allergic to peanuts. So you never really know- that is why I say to stck with pumpkin and sweet potato as your main source of ingredient.
yes or make each treat specific to 1 of them so the ones who can eat oats know what they are buying and same with the peanut butter. My boy has allergies but never found out what they were specifically. I just knew diff foods had diff effects on him and kept switching till I saw none.