About a month ago I had a vet out to the house to look at my six hens, one of whom had a respiratory problem. She examined each one and said they were all on the thin side, based on how prominent their keel bones were. Within two days I switched from Blue Seal organic layer food to regular Blue Seal layer pellets which they have free access to at all times. My question is, how soon can I expect to see a weight change? When I pick them up, it doesn't seem much different than it did. And all of them were tested for worms and the results came back negative so this isn't a parasitic problem.