I heard two stories that made me glow.
A resident here at Lake Park told of a feral cat who gave birth to four kittens then went and got herself hit by a car. The resident then had to buy formula and an eyedropper to feed the little ones. She had a half-grown kitten herself and this kitten got into the box and nurtured the babies and cuddled with them.
And a Facebook friend told of something similar. Her cat had five babies and whenever mama cat took a break her dog would get into bed with the kittens and lick and clean them.