B. S. Reinhart

Colour as a stimulus for the choice of the nesting site by laying hens

Synopsis The preferences of two groups, each consisting of 80 Columbian Rock laying hens, for colour, height of nest from the floor and nest order where a choice was available, were determined. One group was chosen at random, the other was made up of birds that had a more highly developed colour preference as determined at an early age (1 to 12 d). Separate analyses of variance for each group and each level of nest set confirmed that colour significantly affected the choice of nesting site in the group pre‐selected for colour response. Both groups showed very high significant differences between means and between variances in regard to levels. The effect of level of the nest set and the effect of colour and colour nest order combinations were more pronounced in the pre‐selected group, which fact could be an indication of mutual dependency in sensitivity to certain stimuli.

The effect of visual pattern complexity of feeders on food consumption of laying hens

Synopsis One hundred and twenty‐eight commercial laying hens were used to investigate the effects of pattern complexity on quantitative food intake. Independent variables were represented by eight pattern displays placed in trough feeders in the front of birds and exposed for 1 week intervals to groups of four hens in individual cages. As independent variables were also declared the location factors associated with the usual commercial type of hen house (tier levels, sides of the room and distance from working area). Dependent variables were weekly food consumption, egg production, egg weight, egg mass and food utilisation. Prior to the experiment the birds were adapted to the cages for one month. Birds were 24 weeks old at the commencement of the experiment which lasted for 26 weeks. Food consumption was positively effected by chromatic pattern complexity and by colour preference. Effects of complexity of achromatic displays, as used in this study, indicated a similar trend, but were not of such a magnit...

Exencephaly in chicken-pheasant hybrids.

1. The incidence of exencephaly was investigated in chicken-pheasant hybrids. 2. With the pheasant as sire, fertility was 7-6%, but with the fowl it was 19-5%; hatchability of fertile eggs, however, was similar, 42% and 41% respectivley. 3. Only one exencephalic hybrid was obtained when the sire was the pheasant but 70 were noted when the fowl was sire. The incidence of this malformation in hatched chicks was 12 times more in crosses with the fowl as sire than in the reverse cross. 4. The frequency of exencephaly was greater with Rhode Island Red, Barred Leghorn or White Leghorn roosters than with Columbian Rock roosters.

Persistent right oviduct in ring‐necked pheasant

1. A right oviduct, approximately two-thirds the length of the left oviduct, and with a separate opening into the cloaca was observed in a female Ring-necked pheasant. 2. It is suggested that interference of the synthesis of Müllerian inhibiting factor from the gonads may have allowed its development.

The use of selection and strain crossing to reduce egg shell breakage

1. Selection for low egg shell deformation and high egg production was carried out in two White Leghorn strains, M and H, in order to test the feasibility of reducing the incidence of egg breakage without loss in egg production. 2. Selected and control lines were maintained within each strain. 3. After three generations of selection, egg shell deformation was reduced in the M selected line as compared to its control counterpart but this change in deformation was not accompanied by a reduction in egg breakage; however, no reduction in deformation or egg breakage was achieved in the H selected line. 4. Crossing the M and H strains resulted in a reduction of egg breakage in the crosses as compared to the average breakage of the parental strains, suggesting the potential of utilising strain crosses to reduce the incidence of egg shell breakage.

Malpositions in chicken‐pheasant hybrid embryos

Synopsis The occurrence of malpositions in hybrid embryos obtained by two‐way crosses between Ring‐necked pheasants (Phasianus colchicus) and Columbian Rock fowls (Gallus domesticus) was examined and the numbers of the various types of malpositions were recorded. Of the 230 unhatched embryos, the 178 embryos which were detected to be more than 18 d old were classified according to their position in the shell. Of those exhibiting malpositions 68 were males and 52 were females. A X2 analysis revealed that the sex of the embryo and the distribution of positions (normal vs malposition) were not correlated, although there were significant differences amongst the frequencies with which the different malpositions occurred (P<0.001). Since some of the embryos in malposition 2, in which the head is in the narrower end of the shell, were alive at the time of examination, while those in malposition 3, in which the head is turned to the left, were all dead, it is postulated that the former malposition is not always l...