I wouldn't give any more medicines, including the clotrimazole (lotrimin.) It sounds like their guts are a bit sick. I would give them just probiotics (Probios) or a little plain yogurt daily in their food, to try and restore their gut bacteria to normal after all of the antibiotics. Tylan and sulfa are both antibiotics, and with Valbazen to worm them also, they are probably just having runny poops from that. A slow crop may be a result of whatever illness they have been suffering. Vomiting a chicken can be risky, and they can easily choke to death. You can make a mash of a lot of water added to some chicken feed, mix in a small amount of yogurt, and even some raw or chopped egg to get them eating and drinking.