I really hope they turn up but sorry to be negative but were they free ranging un supervised?
If so predators could have taken them, foxes don't always leave signs behind. I hope that isn't the case and they are found safe and well
Unfortunately, it doesn't take long for a fox to jump in a garden. That's how I lost Steffi, as I only popped indoors for half hour and that was during the day and the fox left her body on the lawn. I really hope you find your buns.