I never let mine chew or dig in the bed. If she keeps doing it take her away from the bed and give her something else to chew. If you let her chew, she will chew the plastic one and get little pieces of plastic in her, which is not good. I tell mine stop when ever they try to chew or dig and they know now to stop or they get sprayed with water.
Every time she does it i give her her chew toy to play with instead. I am going to give her some fleecy blankets to sleep on tonight and keep her squishy bed for when shes out in the front room then she'll not be able to chew it unattended then. My husband will gat her a plastic bed tomo. Thanks guys. xxx