Someone brought me 4 unwanted one day old baby pekin ducklings. They are 4 days old now. I noticed that one isn't growing as much as the other 3 and is squatting even when walking most of the time and doesn't stand up all the way much. Its legs look fine. I feed non medicated chick starter mixed with a bit of all flock crumbles and brewers yeast tablets crumbled up. It is eating and drinking normally. Everything else seems normal. Is there anything else I should be doing or giving them?