As of 1.16, this pack had been rendered useless, but there is still a small adjustement i could do. So i made it a bit longer so we can now connect it to tinner block like fence. You can download this for 1.12 up to 1.16.

This pack was way more work than expected. I had some trouble trying to get the model to work properly but i finally got it. Basically this pack contain new models for the iron bars so you can expect the same behaviour from the connected iron bars as usual, but the single post should look like chains.

This pack should work with any other pack since it is only models. I've also added iron_bars_post_single.json that you can use to replace iron_bars_post.json. The reason i did that is because the model i use for the chains is 7 elements for compatibility reason, but iron_bars_post_single.json is only 2 elements and use a different texture. Visually the result are the same but i assume less elements equal less lag so it's up to you. I've also modifier iron_bars_side.json and iron_bars_side_alt.json so i can remove iron_bars_post_ends.json. This is the reason why you have a 2x2 px square which are the same color on top of the bars. It was to avoid texture clipping thew one another

Anyway, you can install this with any other ressource packs in .minecraft/ressourcepacks/ and you should get the proper chains texture by default.

Thanks and enjoy!