Make sure your hen is broody by letting her sit for 5 to 7 days. If she stays on the golf balls that long and you have some chicks that are newly hatched then by all means slip a few under. It is best to wait until night so that she is not so suspicious of what you are doing. I always put the chicks close to her rear end area. Newly hatched chicks will head right under those warm ol feathers and hunker in. If she is a first time mama, you will want to keep an eye on her to make sure she is doing OK. Some hens are great hatchers but not mommas, others are rotten hatchers but great mommas and some can do it all. Let us know how it goes. Also another thing that is good to do is if you are using a bator and you have a hen go broody I will usually candle 5 to 10 eggs and put the good ones under her after about 4 days of being broody. This way you are sure that at least at the time you put the eggs under, they were fertile and growing. Good luck, Jenn