It sounds like they were molting. They can do that in the fall/winter. They quit laying when molting and can look rough as they drop feathers and replace them. I doubt it had anything to do with the feed.
Can you please explain what was going on when that happened? How long had they been on that Purina feed when they stopped laying? How long had they been laying? What time of year was it (spring or fall)? Was it all of them or just some? Which specific Purina feed was it?
It is really...
Good question.
Nope, that 10% is a rule of thumb. I have no scientific evidence to support it. It's something that makes sense to me based on what I've seen. Not just for chickens but for people and animals in general. Everything in moderation.
If you have special needs you are going to...
That feed contains everything they need for a balanced diet. Everything. Vitamins, minerals, protein, fiber. If that is all they eat they will do fine.
The general rule of thumb is that anything else should amount to no more than 10% of their diet and they will still get a balanced diet. In...