Ž .
a Chi-Squared Goodness-of-Fit test Zar, 1984 . Since we could not be sure of the motivation of females preferring neither strain, results were further examined with
females choosing neither strain removed from the analysis to determine male strain bias among the females that made a choice.
3. Results
3.1. Females approaches to males Our first measure of mate preference was based on which male the female ap-
proached first, with the assumption females would approach the most attractive male first. Females approached models cautiously and some females crouched and allopecked
the comb and wattles of the model when in close proximity. Hence, females appeared to react to models as if they were actual males and not simply novel objects. The number
of Inexperienced females choosing broiler breeder strain, laying strain and neither strain,
Ž
2
. did not differ significantly Fig. 3, x s 0.25, P 0.10 . There was no difference in
Ž
2
. female responses after receiving sexual experience
x s 4.47, P 0.10 . Although a
greater number of Experienced females chose neither strain, this difference did not reach Ž
2
. statistical significance x s 4.75, 0.05 - P - 0.10 .
In tests with live males, responses of females were also unaffected by sexual Ž
2
. experience
x s 1.81, P 0.10 . However, live males were a stronger attractant for
females, with only two Inexperienced females and one Experienced female approaching Ž
neither strain, and this preference for live males was statistically significant Inexperi-
2 2
. enced females, x s 6.75, P - 0.05; Experienced females, x s 12.25, P - 0.005 .
Fig. 3. Number of females preferring male models and tethered live males. Statistical significance according to Ž
. Chi-Squared Goodness-of-Fit test k s 3 is presented above the columns.
When females preferring neither strain were removed from the analysis, there was no strain preference among Inexperienced females that made a choice, and although twice
as many Experienced females chose laying strain males than broiler breeder strain Ž
2
. males, this did not reach statistical significance
x s 3.67, 0.05 - P - 0.10 . We
assumed females would first approach the most attractive male, but it is likely that females approached males for a variety of reasons. Some females displayed strong
sexual motivation, adopting a sexual crouch, giving food-type calls and allopecking the male’s comb or wattles. Other females appeared to be exploring and seemed quite
oblivious to the males. No preference for left or right arms of the Y-maze was displayed by either Inexperienced or Experienced females during testing with male models or live
males. Hence, although there was some suggestion that Experienced females were more discriminating and may have some preference for live laying strain males, there was
little evidence of an inherent mate preference based on female approach.
3.2. Females interactions with males The second measure of preference was based on the interactions of females with
males during live male tests. There were significant differences between the number of Ž
females soliciting broiler breeder strain, laying strain and not soliciting either strain Fig. 4, Inexperienced females, x
2
s 6.25, P - 0.05; Experienced females, x
2
s 15.25, .
P - 0.001 . However, when females not soliciting either strain were removed from the Ž
analysis, there were no preferences with respect to male strain solicited Inexperienced
2 2
. females, x s 0.41, P 0.10; Experienced females, x s 0.14, P 0.10 . Although
there was a tendency for more Inexperienced females than Experienced females to Ž
2
solicit males by crouching, this difference did not reach statistical significance x s 7.0,
Fig. 4. Number of females soliciting and copulating with tethered males during preference test. Statistical Ž
. significance according to Chi-Squared Goodness-of-Fit test k s 3 is presented above the columns.
. 0.05 - P - 0.10 . Not all males responded sexually to females, even when presented
with a strong sexual crouch. It was not clear if failure to respond resulted from distraction by the other male in the maze, lack of libido, or male mate preferences.
Conversely, several females copulated two or three times during a single test. Two females copulated with both strains of male during the test and in both cases, females
copulated with the laying strain male first. However, as preference was unclear, these observations were discarded from the analysis. There were significant differences among
the number of females copulating with broiler breeder strain, laying strain and not
Ž
2
copulating with either strain Inexperienced females, x s 9.5, P - 0.01; Experienced
2
. females, x s 12.75, P - 0.005 . However, no strain preference was detected within
Ž
2
females that copulated Inexperienced females x s 1.6, P 0.10; Experienced fe-
2
. males, x s 1.0, P 0.10 . Hence, based on interactions of females with males, there
Ž .
was no evidence to support the notion of preferences or avoidances of particular strains of male.
3.3. Females proximities to males For our third measure of preference, we considered time spent in residence with live
Ž .
males Fig. 5 . Each 15-min test was divided into 30-s periods, so that females could spend a maximum of 30 time periods in each compartment of the maze, resident with
broiler breeder strain, laying strain or neither strain. Because females could move freely between compartments, they could spend time in each of the compartments during one
30-s period and thus, the sum of the time periods for the three locations could be more than 30. When the number of time periods that the females spent in each compartment
were compared, time periods spent with broiler breeder strain and laying strain males
Ž
2
did not differ Inexperienced females, x s 2.47, P 0.10; Experienced females,
Fig. 5. Mean number of 30-s time periods females spent in residence with tethered live males. Statistical Ž
. significance according to Chi-Squared Goodness-of-Fit test k s 3 is presented above the columns.
2
. x
s 0.47, P 0.10 . However, data were highly variable, as some females spent all of the available time with one male and other females moved actively throughout the maze.
Sexual experience did not seem to affect motivation of females to be in close proximity to males, since approximately twice as much time was spent in residence with neither
Ž
2
strain compared with either of the males by both Inexperienced females x
s 25.0, .
Ž
2
. P - 0.001 and Experienced females
x s 27.3, P - 0.001 . Hence, there was no
evidence of a male strain preference based on the number of time periods females spent with males.
3.4. IndiÕidual Õariation We saw some evidence that certain individual males were attractive to females. For
example, Laying strain male 1 was chosen in all six tests in which he was used. Furthermore, in five tests, females approached Laying strain male 1 within 2 min of
being released from the starting box. In four tests, females spent 93 to 100 of time periods in residence with Laying strain male 1, and females solicited and copulated with
Laying strain male 1 during four of the six tests. Of the 10 females that chose the same male during Inexperienced and Experienced trials, seven preferred the laying strain
male. Although Laying strain male 1 was preferred by all three females he was presented to, results involving other pairs of males were inconclusive. One female
consistently preferred Broiler Breeder strain male 8, while another female consistently preferred Laying strain male 8 and the same situation was observed with Pair 9. It is
difficult to know if these differences arose randomly from chance or whether they reflected distinct differences in the preferences of individual females.
3.5. Physical differences between males Since there was no consistency in the preferences by females regarding the males
presented, male morphological traits must not have been of great importance in female choice. Comb size of broiler breeder strain males ranged from 67.5 to 97.5 mm, with a
mean of 73.0 mm and laying strain males had combs ranging in size from 67.5 to 75.0 mm, with a mean of 70.0 mm. In all pairs, broiler breeder strain males had larger combs,
wattles and shanks than did laying strain males. Health status of the males also did not appear to affect females’ choice. When males were autopsied 2 weeks following this
study, we found that four broiler breeder strain males were afflicted with deep pectoral myopathy and each of these males was chosen by at least one female. It is difficult to
know whether these males had been affected during the testing of Inexperienced females, and although two of the males were rejected by all three Experienced females
to which they were presented, two of them were chosen by two of three Experienced females to which they were presented.
4. Discussion
