The basis of the whole system is free-range, where the chickens use 50 % of their daily time to scavenge for insects and weeds. In addition, they are supplemented with grains and by-products from the farm. It has been stated that improving this feeding system has no value, because the genetic capability of local hens does not respond well to this improvement.
However, when commercial strains are introduced, it could and should be quite possible, that with a small addition in supplements, a relatively strong response in performance can be achieved.
It is necessary that more data be collected about the quantity and quality of food that chickens find when they scavenge around, and the interaction with the feeds supplied, so that determined food supplements can be suggested.
In the process of getting more data for a broader view on feed requirements and feeding habits of free range chickens, the following set of data were collected at Muy Muy, Nicaragua, in the course of 1995 / 1996.
The feeding system in Muy Muy was fully based on the supply of a maize supplement to the chickens. In November 1995, a monitoring exercise with 18 families was executed. On two consecutive days per family, how much maize each family gave to their chickens was registered. The overall quantity was corrected for the young stock and the cocks that were around. Weighting factors were: small pullet 0.3, big pullet 0.6 and cocks 0.8. The calculation revealed that every family supplied, on average, 92 grams of maize per adult hen per day. This is a substantial amount, but November is immediately after the harvest.
Feed consumption of 10 layers at a feed bar
The question arose as to what layers would eat if they could have free access to different feeds. Students of a secondary agricultural school designed a feed bar, and registered feed selection and consumption by improved layers on free range. This was done with one family, which had about 10 hybrid layers. (Her local chickens were temporarily passed over to a family member. Rice bran, maize, meat scraps and limestone were supplied ad libitum. On average, over a period of 2 months, the layers consumed the following quantities per day:
Table 1: Feed consumption of 10 hybrid layers on free range
The production of the hybrids during those months more than 80 %.
It was not possible to repeat this experiment. Researchers are challenged to see if they can get the same results elsewhere.
The outcome of this experiment gives some guidance. It gives the impression that if the layers have the possibility of increasing their protein intake, they surely do. The same goes for calcium intake. However, when chickens have the possibility of consuming feed ad lib in the free-range system, it appears that any cost savings on food are eliminated. The economic advantage of no cost feeding is lost, and the aim is just the other way round. The comparative advantage of free range is the feed cost reduction. In this dilemma, the question arises, if it could be economical to keep feed supply restricted to a little maize but supply the layers also with some kernels of soybean meal, or just peas? This recommendation is further validated because analysis of crop contents seem to indicate a level of protein that is too low, a conclusion also reached by Huque (1999).
Calcium (Ca) consumption
It is expected that free range layers need to be supplemented with a Calcium source to achieve a higher egg production level. In Nicaragua, a few times Calcium was supplied to farmers, and they were advised to supplement their layers. Farmers argued, however, that they did not see any effect.
A survey by two students in Nicaragua showed differences between 2 groups, each of 3 families, with hybrid layers on free range, one group with the supplementation of limestone, and the other without. More eggs were produced in the group with limestone. The survey, however, suffered from organisational difficulties.
Huque (1999) found that the Ca content of the feed of scavenging laying hens in Bangladesh was close to the requirements, supporting the observations of the farmers in Nicaragua. If there really is no need to supply a calcium supplement, this would relieve farmers using hybrid layers in the scavenging system of a big burden. It would be good if the results from Bangladesh could be confirmed in other places.