Turn it into a ‘snuffle box’. Put in kitchen roll tubes, loo roll tubes, ripped egg carton boxes and scrunched up paper and then sprinkle kibble inside it for them to find. Demonstrated here by Iris and Watson:
we saw it on Paul O'grady's for the love of dogs... they had a dachshund of a similar age to Norman and with a bit of bad attitude like Norman.... they called it a destruction box, said it gave the dog his sense iof mischief and gave him some outlet for his energies. On the show it calmed him down, so we tried it and it has certainly worked quite amazingly well.