Yeah it is hard.
I introduced those young kidos with the elder ones and I stayed in the coop for many hours then I left them alone when I noticed they were doing fine.
And sorry for bad English
In the previous batch I gave 38 eggs and that was a disaster.Only 12 hatched with 2 of them with disabled legs, they died later.And rest of ithero died after day 16.
I was shocked because when I took out those dead eggs and broke them them to see what's went wrong, I saw that in those dead eggs...