Thanks moxieberry and Isismommy!
I`ve just bought a fabric that maybe is fleece, but i dont know in english the word. Its kinda ugly, purple/brown made of rests of wool with a lot of colored lines mixed. I bought also one thin cotton fabric. I`m going for a 4 layer fabric liner: flannel + cotton + fleece(?) + flannel. Thanks, i hope everything goes all right. I`ll get my first hedgehog on monday!