So sorry about your chick, and sorry for your husband too. You did the right thing for her, but culling is a very hard thing to do, as I learned first hand last week when I had to cull five of ours(the sixth died on her own). My husband would have done it, but he's as tender hearted as I am, and as I was their primary care taker, I thought it best to be done by me.
I live in town, so I couldn't use the gun, and I don't own a pair of scissors sharp enough to do the job, so I called my dad to see what I should do. His advice was to use a large rock, I know that sounds horrible, but when done properly it's even faster and more humane than the scissor method. It also removes the visual of death, as I put them in dark doubled up grocery bags. The rock I used was twice the size of them and heavy, one solid blow and it was over instantly.
I know this method will only work for small chicks, so we'll have to get another plan in place for older girls, when the time comes. We'll be getting our new batch next Monday. I hope I'm ready by then, as I've been suffering from severe anxiety since last Wednesday. I knew taking lives would affect me, but I had no idea how much. Raising chickens is something I really want to do, and I don't want to let one bad experience ruin it for me, but I really hate feeling this way.