This will allow you to feed multiple sites/urls to DNS recon. It can be further expanded to grep for successful zone transfers by throwing some grep successful after the probes.

LoopDNSRecon.sh

#!/bin/bash
#https://github.com/FranklyFuzzy
FILE=$1
while read name
do
    echo "dnsrecon being ran on $name"
    python dnsrecon.py -d $name -t axfr -c output/$name-dns.csv
done < $FILE

#can add - echo "test $name" to confirm reading file by line