22 month old kicking animals

[l1a2u3r4e5n6]

Hi there, just after a bit of advice really, my little boy has started kicking my cats on the odd occasion to which he is put on the naughty step which we have started and he will apologise and then go and say sorry and stroke the cats but he then will do it again a few days later.
His dad (we aren't together) was very verbally abusive to me in front of him last week so i asked him to leave and went to my sisters to play as he has 2 cousins of a similar age and he then started trying to kick their rabbits, he was told off and put on the naughty step of which he doesn't appear to care will happily sit there quietly and apologise but then did it 5 more times until i stopped him playing in the garden, again he didn't seem to care.
I don't know if his dad getting angry at me had affected his behaviour but as he had done it to my cats before i can't put it solely down to that i'm really worried i don't want him to become nasty to animals, luckily being so young i don't thing he actually managed contact because the bunnies ran away. he's never witnessed violence at home and nursery he is good as gold. Any ideas?

Your child does not understand that animals have feelings.
Instead of putting him on the naughty step which obviously has no meaning for him.
You need to go down to your sons level for eye contact and explain in no uncertain terms that it is not okay to hurt animals. Then punish him by taking away something he likes or enjoys.
Since the 1970s research consistently shows that cruelty to animals in childhood is a warning of later violent behaviour. You need to stop this behaviour now.

Don't mean to alarm you but might be best to keep a very close eye on this as he gets older because children who want to hurt animals can have serious psychological issues when they're teenagers and adults. Naughty step definitely isn't working and he obviously doesn't find this a punishment. Perhaps stopping him from playing for a while or taking certain toys away for periods of time and explaining it's because he's hurting the animals that he gets punished etc.

Aggression is quite normal behaviour in 2 year olds and not a sign of future conduct disorders. Keep reinforcing hands and feet are for being kind. I'm sure he will outgrow it.