It's NOT my favorite part of chicken parenting, that's for sure. Baby chicks poo constantly, and 'pasting up' is a possibility. Eric and I take turns checking their little butts every few days to make sure their vents are not blocked. Now that they're over 2 weeks old, there is less of a chance this will happen. Thank heavens! Chirpy does tend to have things build up on her backside and neither Chirpy nor I enjoy the task of clearing the area. While those fluffy chicken butts are rather cute, they can also be problematic. Just ask Stella, aka Princess Poopy Pants!
So, that's probably much more than you wanted to know, but it's all part of the adventure!