I did some research and realized that it's a common thing to put a crapload of sprouts into a pot and sell it, but the individual plants need space! Goodness, if I knew that first I would have saved myself a lot of trouble. I was able to salvage the plants with the strongest stalks, but by the time I got to them, most of them were almost black. At least my bunny enjoyed eating those ones. :/

If plants were grown indoors, they need to be "hardened off." This means you need to keep them in a sheltered location increasing gradually the sun, wind, rain, etc. as the plant becomes accustomed to it. If not, plants can wilt, become broken, or suffer other damage. Perhaps this was the case?

FataMorgana

I'm sorry you had to go through that! I found that basil grows very easy from seeds. I wait until it is warm enough outside and sow some seeds in a small pot. Sometimes I can pull them apart and have more plants, other times you have to just cut off the weaker ones.