Since getting our chicks in September, we have stopped all forms of herbicide/pesticide application on our lawn. The last time weed killer was applied was in June. Turf Royale 21-7-14 was applied in September. It does have some time-released nitrogen. Is it safe to graze my hens now (say 3 1/2 months since application)? We have had one long hard rain and many sprinkler sessions since then. I don't plan on using any more of this toxic stuff now that we have a natural means of fertilizing and weeding! I am very concerned about this because one of my healthy 13 week old chickens just suddenly died. They have been grazing for 2 weeks on this lawn. Could this be the cause? They are quarantined in the run until I find out it's safe. And they are not happy about this! Thanks.