It's going reasonably well except I see a few of the older gals are eating the young ones' medicated feed. Is that okay?
What medicine is in the medicated feed? I don't have a clue what would be the effects of something called "medicine". Might not be much, could be pretty serious. I don't mean to be picking on you, that question is really common. I don't know what country you are in, I don't know what medicated feed is available wherever you might be. In the States where I am different medicated feeds can contain different medicines.
Most medicated feeds here in the states is medicated with Amprolium and only Amprolium. Most, not all. You can find that information on the label. If it is only Amprolium it will not hurt your hens to eat it. The eggs are fine to eat. You could even butcher them and eat the meat. But if it is not Amprolium and only Amprolium I don't know if it is safe or not.
Also, I saw my main egg layer, Big Mama, eat one of the smaller chickens' discarded feather. I'm assuming this may mean a lack of protein issue.
It is extremely common for my chickens to eat a feather floating around. That is a good source of nutrients and absolutely normal. It does not mean anything bad. If they start pecking feathers off of each other to eat, then you have an issue. From what you describe they are just taking advantage of a good nutrient source. When a grasshopper gets into the run I don't see hens stopping to say, I've already had my grasshopper quota for the day, I think I'll skip this one. They take advantage of the opportunity.
In my opinion if they are cleaning the treats up that fast you are not feeding them too many. They do need a balanced diet, but that does not mean you need to micromanage every bite they eat. They can handle quite a bit of variation in the balance of nutrients. If you look at different brands of "Layer" feed, you will find a difference in the analyses. The analysis is on the label and tells you what percent of various nutrients are in that specific feed. You can find differences in protein, fats, fiber, salt, calcium, and the other nutrients they tell you about. They are all going to be roughly the same so they are relatively balanced, but one may have 16% protein, another 18%. Some of us like to feed a 20% protein feed though we may need to offer oyster shell on the side to get the calcium up where it needs to be for hens laying eggs.
We all have our own opinions on these things, you can see how different they are by reading a few posts. Some of us are extremely rigid in what they want, some are more relaxed. In my opinion if your chickens are healthy and laying good eggs you are doing OK.