Spiny Amaranth

I'm having a problem with his weed popping up in my barn yard. I hardly every graze animals through there in the summer but sheep are in there fall through spring. Chickens year round. I actively attacked it last yr but I think my spray was ineffective at best. I used Gordon's 2,4,D in a hand sprayer. I know I got it all before it seeded out so remnant seeds must still be there from previous yrs. Luckily I haven't noticed it pop up in my big grazing pastures.

 

All other weeds I can get by hand, thistle, cocklebur etc. But this stuff is horrible and I need it dead, even if it kills surrounding grass. But I need it to work and disappear somewhat quick so the chickens don't pick it up and put it on my breakfast plate.

 

Looking for something somewhat cost effective I can buy and use. Not a $200 bottle per gallon I will only use once.

 

Any suggestions?

Spiny Amaranth