Greenthumb Lawn Care

I wouldn't let chickens on a lawn that had been treated with anything for at least 7 days - you could try ringing them to find out what chemicals are being used and ask but also besides what they say google the chemicals and then ring other manufacturers/suppliers of these chemicals to find out. Remember they will be using things on the ground to kill weeds and beasties (beasties that your chickens would eat).

 think they use a broadleaf weed killer and a moss killer, wouldnt let my birds anywhere near it until the weeds are dead and removed.
  Alby