My chicks are about a week old now. They arrived on Wednesday. One of them has had issues with pasty butt since they got here. I keep wiping it and it is getting much better. She is eating normal, drinking normal, and overall seems fine. I am starting to worry about her though, because she is still so small. The others seem to grow by the hour, and she seems barely bigger than when she arrived. She is also much less active. When she isn't eating or sleeping, she mostly stands under the heating lamp, snoozing, whereas the others are running around and plotting their escape, trying to use the wings that are growing in. I am feeding medicated feed, have probiotics and electrolytes added to their water, and they get an egg yolk once a day. Is there anything else I could try?