Cat hair loss under collar - how to restore

[moreknow]

I have around 6 feral/semiferal black cats outside, and I would like to distinguish each of them with a breakaway reflective collar. So far i only have one with a collar, and he's always been a skinny male with rough short fur. When i took him to get neutered i asked the staff to put this collar on:
Whisker City® Reflective Stripe Cat Collar

i took the bell off b/c i don't want to torment him with the ringing.
It's been over a month of him wearing it, and it hasn't come off and it doesn't seem to bother him, but he's been losing fur in that area. I am taking some 4 more black cats and i want to have a different colored breakaway collar on each one, and i want to have a Whistle Go cat tracking collar on one of my adopted feral cats that stays inside but spends time exploring outside. It looks like this:

side note: i would like to know what y'all think about these type of products. Does anyone recommend these type of things? i feel like it would really bother them but i see that cat above and i feel that it shouldn't bother them at all

Anyways, I want to help that cat restore his fur and make sure the next cats that will get collars won't lose hair. How can i accomplish that? (The collar doesn't seem tight at all, i can move it around)

Many thanks in advance,
uriel

 

[FeebysOwner]

Hi. Can the collar be replaced with a breakaway harness? Some cats are just more prone to losing hair with collars. Not saying that the same thing won't happen with a harness, but it is worth a try.

 

[moreknow]

i'll see if i can find a red reflective one. I just want to have his hair restored
thank you for your feedback