Marking ears is preferable to collars. They can be dangerous to tiny kittens getting hung up or a limb caught in another’s collar. They are not meant for kittens. Please do not us collars until they are older.
I found out she was pregnant before i got her the babies were not her brothers as it turned out as it was some other cat she lived with at the time. Going back to the baby he is being tube fed overnight because he has a lot of gas in his belly, as of now the other three are nice and chunky and growing as they should he just seems to be a straggler. We don’t know if he‘s going to make it or not time will tell.