I turned a hard to mow area into poultry yard a few years ago. I noticed the next year only a couple ragweed and no cleavers or burdock. None of those the last few years..in that area, everywhere else it is growing. I have seen the turkeys eating the ragweed seeds. Snakeweed is taking over though.
I had to google snakeweed. just to find out I've got tons of it.