It is likely they may in the future, however right now, they don't have kits.
I heard that Vicky hidden that because Stormfur and Brook have kits, but its unknown.
I think Vicky said they would in OOTS
Yes they do, in Sign of the Moon. Lark that Sings at Dawn (Lark)- pale tabby she-cat and Pine that Clings to Rock (Pine)-brown tabby tom are their kits.