I agree with @4yearsofchickens that poison can be used safely. If you carelessly put it when kids, pets or other critters can get to it then shame on you. It doesn't have to have a bad outcome and if there is indiscriminate kill whoever placed the poison was reckless.
Cut down you flock. That's not much feed. I have a lot more birds and I go through around a half ton of feed a month. A half ton is 20 bags. I usually go through around 8 bags a week.
If you place the poison where other pets and critters can get to it then you're not using good judgement. There are safe ways. I use the same rat bait stations but I don't have them where pets and other critters can get to them. Rats are good climbers so the bait stations don't have to be at...