SECTION XII 



DISEASES OF THE ORGANS OF LOCOMOTION 



LEG WEAKNESS 



This is a coiuntion in whieli the ])irds cannot bear their own 

 weJsrht or have difficulty in doing so. It occurs in young as 

 well as in old birds but there is a possibility that the cause 

 in young birds is different from that in old Inrds. Knowledge 

 as "to the causes of leg weakness, so common at times in certain 

 localities, is imperfect. The conditions are being investigated, 

 however, in several laboratories. 



Possible Causes. — In young chicks some of the causes are 

 believed to be improperly heated brooders, too much bottom 

 heat, damp and badly ventilated houses and keeping chicks 

 constantly on wooden floors. We have seen it in our flocks 

 where they were on wooden floors and as soon as they were 

 turned out on dirt runs the disease disappeared. It has been 

 reported where the chicks were kept on cement floors but 

 usually disappearing, as in our experience, when the chicks 

 are allowed to run out on dirt during the warmer part of 

 the day. There is little doubt that overheating and too much 

 under heat is one prime causative factor; for, since the hov- 

 ers supply! nsr top instead of under heat came into common 

 use there does not appear to be so much leg weakness among 

 the baby chicks. It appears to be the artifically-brooded chicks 

 that develop leg weakness and the disease is supposed to be 

 unknown among the natural brooded chicks especially where 

 the hen and brood are provided with the combination sitting 

 and brooding coop. 



Leg weakness may be observed in birds that are heavily 

 fed and that grow^ rapidly and where the birds' weight ap- 

 pears to increase faster than their strength. Overcrowding 

 and close ventilation are no doubt contributing factors. 



In adult birds leg weakness may be due to rheumatism and 

 possibly to some extent this may be the case in younger birds. 

 Cockerels are apparently more often affected than pull (4s. 

 Tt is aj^parently inore prevalent among the heavier breeds 

 than among the lighter ones. 



!^}fi)}pto)ns. — Leg weakness or paralysis among old birds is 

 widespread in the Ignited States. It usually appears sporad- 

 ically and could hardly be considered in the sense of a con- 

 tagion. In addition to the leg weakness which at times results 



