UTILITY CLASSIFICATION 81 
them susceptible to cold. In practice, however, it has been found 
that the birds do not suffer severely if the house is kept well ven- 
tilated. An abundance of fresh air and oxygen keeps up the circu- 
lation of the blood and removes surplus moisture. The presence 
of moist air is very detrimental and tends to produce frozen combs 
in winter. Frozen combs and wattles must be avoided, as they 
impair the physical condition of the birds, and greatly reduce, for 
a time at least, the egg-laying capacity, due to the impaired vitality. 
The close feathering does not offer the protection against cold 
that is found in the meat breeds or loosely feathered birds. A 
thick growth of feathers offers better protection. 
Fic. 49.—Single-comb White Leghorns, the most popular of the egg breeds. (Photo by 
International Correspondence Schools.) 
A reason which is advanced for the breeding of rose-comb birds 
is the supposed hardiness of such combs. In practice, the wattles 
and the spikes of the rose combs are often frozen. It has been 
impossible to breed as high a producing strain of rose-comb birds 
as of single-comb birds. The Leghorns, in spite of the danger of 
suffering from cold, have proved to be one of the hardiest breeds 
kept in this country. For winter egg production, they have proved 
their worth in practically all sections. When provided with proper 
houses and the right kind of feed, they are well able to withstand 
the winters. 
Leghorns outclass all others in popularity for egg-producing 
6 
