I don't know of any other side effects. There is quite a group of people who use this hormone treatment for rescued battery hens. I would expect the comb to be paler on the hormone treatment as the red comb is triggered by hormones and a sign that she is ovulating.
As regards feed, many people feed their whole flock a "grower" or "all flock"/"flock raiser" feed instead of layer feed and offer oyster shell on the side for those birds that are actively laying and need it.... they instinctively know what they need and will eat the oyster shell as they need it. This means that male birds and youngsters and perhaps birds that are moulting, are not taking in excessive calcium that their bodies don't need because they are not producing eggs. Excessive calcium intake has been linked to kidney problems and gout, so feeding a feed that has a lower calcium content like "all flock" or "grower" is safer for them.
Best of luck to you. Gwenny Penny sounds like a great girl and she is fortunate to have such a caring owner.
As regards feed, many people feed their whole flock a "grower" or "all flock"/"flock raiser" feed instead of layer feed and offer oyster shell on the side for those birds that are actively laying and need it.... they instinctively know what they need and will eat the oyster shell as they need it. This means that male birds and youngsters and perhaps birds that are moulting, are not taking in excessive calcium that their bodies don't need because they are not producing eggs. Excessive calcium intake has been linked to kidney problems and gout, so feeding a feed that has a lower calcium content like "all flock" or "grower" is safer for them.
Best of luck to you. Gwenny Penny sounds like a great girl and she is fortunate to have such a caring owner.