Chewing is a soothing/calming activity for dogs.
Theres a number of ways to approach this :
1. Get them chew toys to self sooth on.
2. Give them more stimulation and engagement: play with them, take them for walks for exercise and sniffing. (Sniffing the world is very stimulating for dogs - its half fhe fun of the walk for them).
3. Try and find out what possible reason tje dog is 'anxious' and needing to self soothe:
- it it a new environment?
- its there something new IN their environment?
- has there been any type of change in their life, routine, people etc?
- are they in hiddem pain (this can come with age).
If a dog changes behaviour - there has to be a reason that triggers it.
Also....be careful of the chewing of the blankets - you wouldnt want it to end up in a bowel obstruction.
I hope you find a solution.