I have a friend who started an animal shelter.
Do they have a no kill policy? Except for sick animals of course.
I don't even think she kills sick ones.  Gets vet donations to help them.  She mostly has dogs and cats, but I think a couple mules too.
Well it would be inhumane to not kill sick animals that have no chance of recovery... Even in no-kill animal shelters they push for 90% recovery rate to be adopted out.