This is a Proof of Principle study with a treatment ("Intervention") group and a parallel control group for delivering eggshell powder to mothers in the setting of a chilken intervention. The control and intervention groups will come from the same region in southern Ethiopia where fluorosis is known to occur, with active intervention for 6 months followed by observation for a further 6 months. The Intervention is providing daily eggshell calcium to a subset of mothers, with all eligible young children receiving at least one egg a day. The treatment group consists of mothers and young children in a community where study families will receive two chickens each, and the control group are mothers and young children not having chickens for the first six months, but who will be gifted with chickens at 6 months. Along with receiving chickens, the intervention group will receive training in use of egg, as well as assistance in caring for chickens, throughout the first 6 months. In the second 6-months, the participants' use of eggs will be monitored. In the control group, provision of chickens after 6 months will be accompanied by training but for a shorter duration, and monitoring of use of egg will provide information on whether minimal support can effectively allow for adoption of new food sources into a community.

Study participants are all mothers with children aged between 6-18 months old in two participating kebeles (villages), one randomly assigned as intervention, the other as control. The age group of the child is selected because it is the time of introduction of complementary food and it will be easier to see the clear effect of egg on the children's growth. Mothers are lactating therefore at a time for maximal calcium utilization. While eggs are not commonly eaten in rural Ethiopia, it is due to expense, not to unfamiliarity. In the Intervention community prior to baseline measurements, each family of the mother-child pair will receive two chickens at a "ceremony" that marks the responsibility given to the family to provide one egg per day to the child. In a subset of mothers, they will consent to use eggshell. This is modified from what the investigators did in a pilot study (NCT02791100) and the investigators found use of egg by the child was 85% throughout the 6 month time-period. One lesson learned was to purchase older chickens that are immediately capable of laying eggs. Second, in this intervention the child will not receive ESP.

There will be formal follow-up observation at one community site with focus group discussion and key informant interviews, as a way to assess feasibility and practically of chicken donation in the future. This will be a convenience sample representing participant parents, community leaders, Agriculture Extension workers, Health extension workers, persons who were not directly involved. Those targeted for interviews will be the extension workers from whom feedback will be provided, while focus groups will be held with others who are able to attend a focus group session.

Data checks will be provided by two doctoral students working on the project. Local supervisors will provide guidance. The students have written specific operating procedures (SOP) for all procedures. Missing data will be accounted for, but as this is a community based study group means will be used for most outcome measurements. Comparing of two means/the differences of means between the intervention and control groups will be done using independent two sample t-test. Continuous outcomes will be analyzed using paired t-test. Bivariate analysis will be used to see the overall effect of independent variables and then further multivariate analysis (multiple linear regressions) will be done to see the effect of each independent variable. Both crude and adjusted risk ratio with 95% confidence interval will be reported. Other variables and relevant findings will be also analyzed using proper statistical test/analysis techniques and reported accordingly. P-value of less than 0.05 will be taken as significant