Brookside is a good, family run company. They do seem to get overwhelmed from time to time, but the last time I checked their website they gave you a shipping warning right up front.
They were my preferred source for slate before another company that I buy glass from started carrying the slate also at unbeatable prices.
A young Wisconsin teen contacted me last year and wanted to learn to make calls so I hooked him up with Brookside and gave him one lesson at a local Taco Bell. He started making calls for his family. I'm also planning to run a youth call making program at an NWTF even this summer and will buy my supplies from Brookside.
You can find a lot of turkey pot (slate) call making information including links to suppliers and how to's at the link above.
If you need help I'm in WI despite the profile and willing to help.
good luck, dv
Here is the DIY section that has a three part series on making pot (slate) calls and conditioning glass calls.
There are links to suppliers on DV's Links page.
happy turning, dv