20 N. H. Agr. Experiment Station [Bulletin 256 



Other Poultry Studies 



Vitamin A Requirements of Chicks. Varying levels of cod liver oil 

 were fed in addition to a basal ration otherwise deficient in vitamin 

 A. An ultra-violet lamp was used to irradiate the chicks daily in 

 order to he sure of sufficient vitamin 1). The results reported by H. 

 (). Stuart indicate that a ration should have other sources of vitamin 

 A in addition to that supplied by the usual amount of cod-liver oil. 

 These groups showed marked kidney injury and microscopic examina- 

 tion of the manure indicated vitamin-A deficiency. 



Control groups fed only the basal ration without cod liver oil 

 showed no retardation effect in their growth by the deficiency of vita- 

 min A. No symptoms of vitamin-A deficiency were observed in a 

 reserve group fed the normal ration. (Purnell Fund) 



Ti'ials of Irradiated Substances. Three groups of 60 chicks each 

 were fed rations containing one-fourth per cent of irradiated yeast, 

 one-half per cent and one per cent of irradiated ergosterol respectively. 

 Growth was deemed satisfactory under the conditions, and rickets was 

 not observed in any of the groups, reports H. 0. Stuart. The irradi- 

 ated ergosterol was diluted with corn oil to the recommended standard- 

 ization in potency approximating cod-liver oil and computations made 

 on that basis. {State) 



Rapid Feathering Helped to Prevent Bare Backs. With previous 

 data on the subject used as a basis, a breeding pen of rapid-feathering 

 birds was selected by H. 0. Stuart and T. B. Charles to compare with 

 slow-feathering strains. Chicks hatched from the former were par- 

 ticularly well feathered before reaching broiler age, whereas a large 

 percentage of bare-back broilers was noticeable from the latter under 

 the same conditions of brooding. {Purnell) 



Temperatures in Battery Brooding. During the first part of the 

 brooding season H. (). Stuart and T. B. Charles noticed that a high 

 percentage of chickens developed a slipped-ligament condition of the 

 hock under a high-brooding temperature. Subsequent groups brooded 

 under identical conditions other than a reduction in temperature were 

 affected in only a slight percentage of the chicks. This indicates 

 that too high a battery-brooder temperature during the first few weeks 

 may be a contributing factor in the development of this abnormality. 

 {State) 



Control of Cannibalism. Pine boughs, supplied daily to two pens 

 of 200 birds each, proved effective in controlling an outbreak of can- 

 nibalism. H. O. Stuart and T. B. Charles report that other factors 

 which may be of assistance are tipping beaks, removing individual 

 cannibalistic birds, supplying green food, supplying fresh meat for 

 consumption, darkening nests and house, keeping the birds active by 

 more frequent feeding, meat scrap placed in an open hopper, and con- 

 densed milk feeding. {State) 



Certification of Poultry 



Certification of poultry is increasing rapidly in New Hampshire. 

 The first year, .Inly, 1927, to .Inly, 1928, approximately 26,000 birds 

 were handled. The number jumped to approximately 40,000 the next 

 two years and will probably exceed that number this season. 



