Does the galGal5 chicken assembly have a chromosome 29?
The current ensembl entry doesn't have a 29 either.  The archived ensembl assembly  lacks 29 30, and 31 and 33 and LGE64.

The chromosomes after 30 are tiny, so they might not be visible in a karyotype.  They probably realized that "chr 29" was really attached to some other chromosome.