A series of trials was conducted to determine if adding a Lactobacillus fermentation product (LAC) to the feed of laying hens would improve their production performance. Feeding a liquid, nonviable LAC product to either cage or floor housed laying hens did not improve hen-day egg production, feed efficiency, nor egg size during a 48 week experimental period. Laying hens fed a dried, nonviable LAC product did not show any improvement in hen-day egg production nor feed efficiency compared with laying hens fed no LAC or zinc bacitracin. Addition of a viable LAC product to ratios of differing protein levels did not improve hen-day egg production, livability, or egg size of laying hens.

Three experiments were conducted to investigate the influence of toe-clipping and bird density on laying hen performance. Toe-clipping was done on day-old chicks by removal of the digital claws from the front toes. Toe-clipped (TC) and intact (IN) pullets were assigned randomly to laying cages (Experiments 1 and 2, 19 weeks of age) or housed in similar body weight groups (Experiment 3, 18 weeks of age) at caging densities of either 4 (465 cm2/hen) or 5 (372 cm2/hen) hens per cage. Experiment 3 body weight groups were: heavy (greater than or equal to 1475 g), medium (greater than or equal to 1375 g, but less than 1475 g), light (greater than or equal to 1275 g, but less than 1375 g), and extra light (less than 1275 g). Body weights were determined at various ages during the grow-out and egg-laying periods. Beginning at 22 weeks of age, average daily egg weight, feed consumption, feed conversion, hen-day egg production, and mortality measures were made for 12 periods of lay of 28 days each. In Experiments 1 and 2, IN pullets were consistently heavier throughout the grow-out period and consumed significantly more feed during the egg laying period than TC birds. Significantly greater average daily egg weights were found in IN than in TC hens in Experiment 1 but not in Experiment 2. Increasing the number of hens from 4 to 5 hens per cage resulted in a significant reduction in feed intake and body weight gain in Experiments 1, 2, and 3. In Experiment 1, mean daily egg weight was significantly increased (.11 g) upon crowding. In Experiment 2, crowding elevated mortality. In Experiments 1 and 2, but not 3, a significant toe treatment by bird density interaction was observed for hen-day egg production. The IN birds had lowered hen-day egg production rates when crowded than when they were afforded more space, whereas hen-day egg production was elevated in crowded TC hens when compared to TC hens housed at the less crowded density. In Experiment 3, an initial (4 weeks of age) significant depression in pullet body weight was found in the TC pullets but disappeared by the 8th week. Feed usage was also significantly greater in IN than in TC hens in Experiment 3. Toe treatment did not affect any other hen performance variable measured. Egg weight, feed intake, and feed conversion measures varied by body weight groups. In general, the heavier hens consumed more feed and laid heavier eggs, but they were less efficient in converting feed into eggs.

Three trials were conducted to determine if the age at start of limited feeding or the amount of time laying hens were given to consume feed could be used to reduce feed intake without affecting egg weight (EW) or egg production. The age at start of limiting feed did not affect hen-day egg production (HDEP) or EW in any trial. In Trial 2, a significant difference in HDEP due to feeding times at 26 weeks of age was observed. Laying hens fed 7 hr/day at 26 weeks of age had a significantly lower HDEP than any other feeding time. Limited feeding in Trials 1 and 2 significantly decreased feed consumption, body weight gain (WG), and EW when compared with laying hens fed ad libitum. No difference in HDEP or EW was observed due to limited feeding in Trial 3. Laying hens fed 9 or 10 hr/day gained significantly less weight than laying hens fed ad libitum (Trial 3). Limited feeding did not improve feed efficiency in any trial. No consistent improvement in mortality could be attributed to limited feeding.

Data from a previously reported study investigating the interaction of toe-clipping and stocking density on laying-hen performance were subjected to economic analyses to determine optimal profit-producing combinations of these two management practices. In three separate trials, toe-clipped (TC) and intact (IN) pullets were examined at caging densities of either 4 (465 cm2/hen) or 5 (372 cm2/hen) birds per cage. In each trial, beginning at 22 wk of age, hen production performance (hen-day egg production, hen-housed egg production, feed consumption, body weight, and mortality) was assessed for 12 28-day periods of lay. Performance criteria were averaged over all trials and used to determine per cage returns ($) above feed and pullet rearing costs (irrespective of fixed costs) and per cage profits (gross returns minus total costs) for the four treatment combinations. Economic analyses were also adjusted for hatchery toe-clipping costs. Profits (or losses) from each toe treatment stocking-density combination were calculated under variable egg and feed prices. At a blended egg price of $.35/doz, all cage systems lost money. Housing hen TC, 5/cage, yielded the greatest profits or least losses in 76% of the toe treatment stocking-density combinations studied. Economic returns were greatest for TC hens, 5/cage, at an egg price of $.55/doz when feed costs ranged from $140 to $230/ton and at egg prices higher than $.55/doz, regardless of feed prices. However, when these price combinations exist, housing hens IN, 4/cage is more profitable than housing hens TC, 4/cage.(ABSTRACT TRUNCATED AT 250 WORDS)