[Stones] HEALTH: any unrelated piggies with stones?

[Cindy]

I really appreciate your help, Tex.  Tumbleweed does get quite a lot of 
exercise (Friday has dedicated himself to ensuring that), and I am 
trying to encourage him to drink more water.  Since Sunshine passed 
away, Tumbleweed seems not to know that he can drink water when he's in 
his cage!  As soon as I put him out on the floor, he decides he will 
drink.  Yes, I hope it is sludge and not stones.  Thanks so much for 
your help.

Cindy, Tumbleweed, and Friday, missing Sunshine