I like to do a general check over at the beginning and end of the day. I’ll look for weird poops or odd behavior while I fill up food and water. As for a more thorough look, I round up all my birds on Sunday (because that’s my day off) and feel them over, check feet, look at their vents, etc. If I’m concerned about anyone in particular, I’ll keep track of their weight as well. I’m sure this is a bit overkill, but I’ve always done this for my pet birds and I figured I had time for the breeders anyways. Most important thing I’ve learned: keep track of what’s normal and anything abnormal. I like to keep everything in a google doc with pictures but if your memory is better, take a mental note of what their normal behavior and appearance is.