Regarding the price of crawfish, I'm not sure what long term benefit you might get from putting 1,000 lbs. in, but if the money is not really a concern, then I don't think it hurts anything.
You do need to be aware of one type of craw (rusticus .....or something like that) that could have negative effects on existing craw populations.
Excerpt from Robert Crais' "The Monkey's Raincoat:" "She took another microscopic bite of her sandwich, then pushed it away. Maybe she absorbed nutrients from her surroundings."