Sounds good and really nice from the vet not to charge you! Here most people would have grabbed the next solid stick, beat the chicken to death, rip it apart and quickly barbecue it.
C'mon as someone else already pointed out, you are if at all* entitled to whatever a chick like this would cost in the age it had when it was killed. That is anything .
*Might depend on local legislations, are dogs allowed to have a free run, does one need to enclose his property and alike...