How many {field of work} are to/by {poultry farming} ?
How many professions are related to poultry farming?
How many careers are related to poultry farming?
SELECT ( COUNT ( ?g ) AS ?p ) { ?g property:field_of_work resource:poultry_farming }
SELECT (COUNT(?sub) AS ?subs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> ?sub .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P101> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q861182 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P101 wd:Q861182 }
3