Prrkitty give your peeps that are weak all the fruit you can get from the store. If you can only get one or two fruits give them to the weakest peep. I had one peep that got real sick, and his health bar was way past the half way mark on the weak side. I gave him three fruits that I'd kept in the tooltray for praising and his health bar went up to the almost full mark. The fruit will take their health bar up faster than anything else. The vitamins also help. It's most important to make sure they get three meals a day. Also when they're weak make them get more sleep. I've found all the things above work real well.