The babies should feed and water themselves if you have food and water available, and IF mama doesn't insist they stay under her until she is done. She may or may not, it varies from hen to hen. However, they cannot protect themselves so they have to be kept in a safe, nonescapable area, away from other grown chickens. Also, as I said before, you may need to put a heat lamp in for them if they cannot fit under the mom with the other eggs or if she won't let them.
As for the smushed chicks/eggs, it does sound like she is not sitting delicately enough and is squishing them. Most broodies will keep themselves slightly lifted when the eggs are hatching so as not to smash or suffocate them. But some just don't seem to have the coordination for it. I have an australorp that's like that. If you have an incubator, then I would take the eggs and finish them in the incubator if it were me. Let her relax and take care of the bub.
If a hen goes broody once, chances are they will do so again. How often just depends on the hen. Some of mine go broody once or twice a year, others go broody again almost as soon as they finishing raising the last set.
As for the smushed chicks/eggs, it does sound like she is not sitting delicately enough and is squishing them. Most broodies will keep themselves slightly lifted when the eggs are hatching so as not to smash or suffocate them. But some just don't seem to have the coordination for it. I have an australorp that's like that. If you have an incubator, then I would take the eggs and finish them in the incubator if it were me. Let her relax and take care of the bub.
If a hen goes broody once, chances are they will do so again. How often just depends on the hen. Some of mine go broody once or twice a year, others go broody again almost as soon as they finishing raising the last set.