EXPERIMENTS WITH OSTRICHES—XIII. 
THE INFLUENCE OF NUTRITION, SEASON AND QUILLING ON 
THE FEATHER CROP. 
By Prof. J. E. Duerven, M.Sc., Ph.D., A.R.C.S., Rhodes’ University 
College, Grahamstown. 
With the extended experience of ostrich farming in South Africa, 
conducted under the most varied conditions, more and more facts are 
being accumulated as to the management of the bird, the whole purpose 
of which is the production of the finest feather crop possible. There are, 
however, yet many points upon which further experiment and investiga- 
tion are needed to explain the varied results obtained; and perhaps no 
subject is more puzzling than that of the conditions under which a full 
and perfect crop of feathers can be assured. Too frequently an ostrich 
which has given a complete clipping of superior plumes will, on the next 
oceasion, produce a nearly worthless crop, the feathers irregular in size and 
defective, and accompanied by many “ blanks.’’ The object of the present 
article is to draw attention to some of the conditions under which such 
incomplete crops are produced, in the hope that discussion thereon may 
bring forth the experience of others, and thereby lead to some solution 
of the difficulty. 
Tue INFLUENCE or NutTRITION. 
It is now accepted that to ensure a full and complete clipping of 
feathers, the bird must be in a high nutritive condition when quilled. The 
necessity for this in the starting of the crop has been impressed upon 
every ostrich farmer from his own experience, and has much to do with 
the increasing production of iucerne, rape, and other crops as food for the 
birds. No one now thinks of quilling birds during a drought or at such 
times as a plentiful food supply is lacking. The power of the bird to 
produce a complete and perfect clipping is found to be a more delicate 
matter than would have been expected from such a strong and vigorous 
animal as an ostrich, and among the influences concerned, nutrition must 
undoubtedly be placed first. Feathers are formed from the epidermal or 
outer layer of cells of the body, and these are highly responsive to a vary- 
ing nutrition. 
An Improvinc Nurritive Conprtion DESIRABLE. 
It is somewhat difficult under farming conditions in South Africa to 
keep an ostrich under equally good nutritive conditions all the year round, 
and this is not altogether necessary. The most critical period for the 
feather crop is during the early months of the growth of the feathers. A 
