I didn't exactly grow this as a crop "on purpose." I bought Chia seeds at a local health food store, soaked them and spread them onto a ChiaPet for fun. They grew quickly and then started to decline. So I peeled the "coat" off the ChiaPet and laid it on the ground in my garden. It grew so fast! It got dappled sun from early morning until around noon or so. Nothing here seemed to bother it (pests, disease, etc...)

Very easy to grow, as long as you soak the seeds first. A friend of mine tried to get his ChiaPet to grow faster, so he skipped the soaking and just wet the seeds and spread them onto his "pet." The difference was shocking! Definitely soak!

shear, when did you plant? did they flower and make seeds? how big did they get? how long to maturity? The way you describe it, they started out very thick. Did most survive to maturity of did they "self-thin".
Does anyone else have any information? From what I found, the end of the hurricane season would be the time to plant. One site I found recommended 1/4 cup of seed per square foot. That sounds like a lot to me. They supposedly get up to two feet tall.

I spread them on the chia pet probably in April I'd guess. About 2-3 weeks later, I laid the "pelt" on the ground and watered it for maybe 3 days (because I didn't expect it to work!)
They did eventually die of "self thinning." Before that, they grew to about 18 inches tall, very lush and beautiful. No flowers (that I saw/was aware of), and no "volunteers" this year... though I disturbed that area quite a bit, on purpose, this year. I personally feel they weren't getting enough sun.
I wish I had more information, but I hope this adds something for you!