That will work the first night. After that the rodents will just start eating more during the day.I am looking for a bucket that will fit over my bigger (30#) feeders.
My 7# feeder fits inside a 5 gallon bucket. At night I am dropping it and putting an upside down bucket on it.
Do this, empty your feeder and weigh the feed. The next day at the same time of day re weigh the feed. If you are feeding more than 1/4 pound per day per hen (ignore the roosters) you are feeding rodents or wild birds. Now figure out the savings each day and see how long till you pay for a good feeder. Plus a healthier flock with fewer lice infestations from the vermin bringing it and disease into the coop.