▁presented ▁major ▁disease ▁challeng es . ▁ ▁Studies ▁have ▁shown ▁that ▁small ▁scale , ▁back yard ▁ch icken ▁keeping / eg g ▁production ▁reduces ▁these ▁potential ▁disease ▁ris ks . ▁ ▁According ▁to ▁Men ch ▁et ▁al ., ▁although ▁changes ▁in ▁commercial ▁egg ▁production ▁systems ▁are ▁being ▁driven ▁largely ▁by ▁animal ▁w elf are ▁concerns , ▁it ▁is ▁clear ▁that ▁other ▁aspects ▁of ▁such ▁changes ▁must ▁be ▁considered ▁to ▁ensure ▁sust ain able ▁egg ▁production . ▁S ust ain ability ▁is ▁a ▁complex ▁topic . ▁Element s ▁of ▁sust ain ability ▁include ▁econom ics , ▁environmental ▁effects , ▁human ▁health ▁and ▁safety , ▁and ▁social ▁values ▁in ▁addition ▁to ▁animal ▁w elf are . ▁Back yard ▁egg ▁production ▁has ▁been ▁suggested ▁as ▁a ▁solution ▁to ▁sust ain able , ▁health y ▁food ▁supply ▁for ▁families . ▁ ▁Bre eds ▁ ▁While ▁there ▁are ▁over ▁ 3 0 0 ▁different ▁bre eds ▁of ▁ch ick ens , ▁most ▁people ▁choose ▁between ▁a ▁select ▁few ▁bre eds . ▁Most ▁ch icken ▁own ers ▁are ▁looking ▁for ▁a ▁high - produ cing ▁egg ▁layer , ▁cold - ▁and ▁heat - hard y , ▁do cile , ▁quiet , ▁non - bro ody , ▁and ▁a est het ically ▁ple asing ▁ch icken ▁bre ed . ▁Many ▁commercial ▁ch ick ens ▁raised ▁in ▁fact ories ▁for ▁white ▁eggs ▁are ▁white ▁leg horn s . ▁This ▁bre ed ▁is ▁no isy , ▁but ▁has ▁a ▁very ▁high ▁production ▁of ▁eggs ▁and ▁rarely ▁go ▁bro ody , ▁and ▁they