I have two 1 year old Pekin ducks and they are always being nosy and getting into things. I wed and fed my grass last night at about 7 pm and they where in bed already. I ran my sprinklers in the morning at about 6am, and the ducks came out at about 10:30am- they immediately go and eat the grass. Is this safe?? the weed and feed was most likely soaked in by the sprinklers but I'm nervous they will get sick!!