I started using this product after one of my chickens became sick (and recovered with vet care and nursing). One of the possibilities was thiamine deficiency, despite her being on a commercial layer pellet. I'd also been reading about the nutritional value of eggs, and it made sense to supplement my chickens so they could pass on more nutritional value through their eggs. After the first round of 5 days treatment, they have gone from 3 hens laying 1 egg every second day, to 3 per day! An unexpected side effect, but to me shows they must be feeling more healthy. I will keep using regularly for sure!