Hi Zaid  Al- Rubaiee

I would suggest u to go for direct isolation of the fungi , by just placing  the feather in Basal salt medium with antibacterial agent .  Try to isolate those fungi which grows on the surface of feather and reinoculate it on the Casein medium.  You can also visit  areas where the slaughter house waste are dumped . collect the feather samples from there along with soil . There you have more chances to get microbes which are capable of degrading keratins.  

Thank you Sp Ranju

There is an method refer that the fungus can consumed keratin (degrade feathers)?

1.Ecology of Keratinophilic fungi ohttp://link.springer.com/article/10.1007%2FBF03053134#page-1

2.Keratinophilic Fungi: Nature's Keratin Degrading Machines! http://www.ias.ac.in/resonance/Volumes/08/09/0028-0040.pdf

3.Isolation and Molecular Identification of Keratinophilic Fungi from Public Parks Soil in Shiraz, Iran

http://www.hindawi.com/journals/bmri/2013/619576/