My first little batch of chicks is getting big - they're mostly feathered but for their heads and have easily quadrupled in size since I purchased them about a month ago. They love to perch on my forearm, so I moved them into a larger cage with two nice perches... and they NEVER go on them! Last night I found them both perched on the brim of their water dish, filling it up with poo, about a foot away from the perches. Do I need to show them how to get up there, or...?