one of my ducklings that hatched yesterday has a bent leg/foot. Otherwise he seems fine, but the leg makes him not be able to get around well and he has flipped on his back a couple of times because of it. Is this something he can grow with or will he not make it? I don’t know what I should do for him. Any advice would be appreciated.
If the duckling is eating/drinking/pooping normally, I'd say it has a chance at a good quality of life...and possibly even good use of its foot with some intervention. I'd try to get the foot into a normal position with a "shoe" so that it can learn to use it normally early on. While the linked thread features a duckling with what appears to be a different foot problem, there are helpful photos of the foot brace.
Additional nutritional support in the form of vitamin supplements would also be good, in case there's an underlying nutritional cause. @Miss Lydia and @Amiga have helpful suggestions in this thread, too.
I think the information @FoodFreedomNow has given is excellent. Please do the shoe getting the foot in normal position at as early an age as possible is the best advise I can give plus starting all your ducklings on Liquid b complex for leg strength.