Hi-Yield Snake Repellent should be reapplied every 2 weeks until control is maintained. If it were to down pour with rain you may need to reapply sooner.
Yes, Hi Yield Snake Repellent is safe for use around and in a chicken coop. It will not harm any animals. It is just a repellent and will keep snakes out of the area.
Per the product label, one pound of the Hi-Yield Snake Repellent will treat a band 8 inches wide by 50 feet in length, so the 4lb bag would be enough to treat 200 linear feet in an 8 inch wide band. You will not be applying a complete barrier around the yard, you will only be treating 3 sides. This is necessary to allow an exit point for any snakes that are on the inside of the property, otherwise, they will not be able to leave and will be trapped. Measure the linear footage of the fence line and exterior perimeter of the home to determine how much you will need.
The shelf life of Hi-Yield Snake Repellent is 4-6 years as long as the product is stored in a temperature controlled environment where it will not be exposed to moisture.
As long as you keep pets/children out of the area while you treat and until the Hi-Yield Snake Repellent has had time to completely settle, it is safe for pets and people to return and resume normal activity. Typically after a few hours it is safe to return to treated areas.