There were a couple of threads similar to this earlier this year.
Unfortunately it appears that very few (if any) of the commercial people are interested in doing these sort of smallholder numbers.
I talked to a guy local to me who does it as a small business but he doesn't do small numbers, although he gets asked about it regularly.
he has to charge too much per bird to cover his costs, i'm sure it was £4 per chicken and £20 per turkey, i'll look for the other thread though.
Are you doing these for your own consumption?