I will tell you from a cattle owners' prospective, they are extremely thin to the point of several look emaciated.
Possible plan.... call the owner and say someone stopped at your house and said "your cattle" looked like they were very very thin and that you needed to feed them (or something to this effect).... and you told them that they were not your cattle, that you didn't know who they belonged to..... gets you off the hook.... and tell the owner that you thought you should pass it on as they seem to be trying to reach under the fence for anything they can get to eat.... see what happens in a week and if they are not fed anything then call whoever you need to. There are some pretty strict laws about starving animals and in my opinion they are starving....
We run a cow - calf operation and unless an animal is sick or has a bad case of worms that we are treating for, I have never had an animal get that thin in my life. Feed them or sell them.....
I admire that you want them to survive on more than the thin air.... yes, turn them in if a phone call does not produce results in them getting fed within a week....
NO EXCUSE for starving an animal.
A beef cow should not be showing any ribs if they are in good flesh. Literally, we seldom if ever see the ribs, let alone the hips and pins like these are showing.... That is very unacceptable.
And no, I don't pull any punches when I give an opinion....