I ended up treating in the spring and fall, but essentially two different areas of the lawn. I didn't have chickens at the time, but I'm with you...I don't think I would have treated anywhere near their run (we don't let them free range in the actual yard, anyways, but still...)
The optimal time is definitely in the late summer. I did do one spring application and it seemed to stop the damage area. I have an area on the far edge of my property I'm watching right now, the only area I've never treated. I'd like to hit it before they hatch and lay more in the areas I've already treated, so I'm waiting for the right conditions. I need the soil temp to be above 44F and for it to be a nice cloudy wet day (like today). Might get the temp high enough next week, we'll see.