Tolerance of white leghorn hens to iron in drinking water

Although a number of extension publications and magazine articles state tolerance levels for iron in poultry water supplies, there appears to be a paucity of scientific literature containing supporting data. The standard of 0.3 ppm is often recommended and is based on preventing taste and staining problems for humans. At the other end of the spectrum is a publication that says there is no evidence that iron will cause problems with poultry. Three experiments, each lasting 28 d, were conducted with caged laying hens in an attempt to determine if iron toxicity could be a real problem. Treatment levels for the three studies were, respectively, 0, 0.5, 1, 2, 4, or 8 ppm iron in Experiment 1; 0, 4, 8, 16, or 24 ppm in Experiment 2, and 0, 100, 200, 300, 400, or 500 ppm during Experiment 3 from ferrous sulfate added to drinking water. It appears from these studies that the laying hen's tolerance for iron in drinking water was somewhere between 24 and 100 ppm and that performance should not be adversely affected by the practical iron levels found in poultry water supplies.