Why my chins' coat became thin and lost shine?

[hkkjstwcl]

I have my chins about 6 months to 15 month now. Some of my chins' coat become less attractive since I got them.
I feed them timothy hay and Oxbow pellets. I would give them chin cookies once a week or less.
Do you have any idea as to why?
Boys fought a bit in the past, but I am talking about them in general.
They are healthy and all , but just that I feel that their coats looked better before.
Also, they seemed to have lost weight since they got here.
I think that previous owners were feeding them crap, but do you have any suggestions as to what I can fatten them up a bit and make their coat shine?

 

[Riven]

You can offer a supplement if they are not getting enough oils. You also need to determine if they are just thinner, or if they are thin. Chins can be too fat, like a person eating junk food.

I would also have a fecal done to make sure you don't have a internal parasite, they can cause weight loss and poor condition and sometimes show no symptoms until they are very heavily infested. You can call your vet and probably just take in some fresh poo.

 

[kendra]

I know a lot of people supplement with lifeline, what type of dust are you using- the kaytee stuff isn't very good. Someone else will chime in I'm sure with better info hopefully!