Java placing objects on map according to specified population numbers and ratios of such populations

My project is a simple agent based simulation that models the spread of disease. The simulation consists of agents and map, the classes that belong to agents are: Civil, Medic and Animal. Currently I'm trying to fill the map according to the size of populations: noMedics, noCivils, noAnimals and amount of healthy, ill, and immune agents that should add up to total population of both humans and animals. The way that health status of an agent is determined is simple - random.nextInt(3), 0 being healthy, 1 ill and 2 immune. The way that I would usually fill the map with one of the agent class is as follows:

        for (int i=0; i<noAnimals; i++) {
            IAgent animal = new Animal(map, rnd.nextInt(3), 2, 3);
            agentList.add(animal);
        }

However the issue arises whenever I would try to implement the remaining parameters of simulation that is: noHealthy, noImmune, noIll. I can't seem to find a loop or condition that would fullfill my need which is to "fairly" fill the map with all agents of in the given createAgents() method. Create agents takes 6 parameters: noHealthy, noImmune, noIll, noAnimals, noCivil, noMedics. I've tried few things already but the one that compiles and runs correctly so far is as follows: I'm creating a loop that runs from currNoImmune until noImmune from parameters and whenever a condition sumForImmune < halfNoAnimals && currNoImmune <= noImmune is fulfilled it adds an animal to the simulation and increments sumForImmune and currNoImmune once. The reverse check is done for civlians sumForImmune >= halfNoAnimals && currNoImmune <= noImmune incrementing the same variables and adding a civil to the simulation. Here is the code for method I've described:

        while (sumForImmune <= noImmune) {
            if (sumForImmune < halfNoAnimals && currNoImmune <= noImmune) {
                agentList.add(new Animal(map, 2, 0, 2));
                sumForImmune++;
                currNoImmune++;
            }
            if (sumForImmune >= halfNoAnimals && currNoImmune <= noImmune) {
                agentList.add(new Civil(map, 2, 0, 2));
                sumForImmune++;
                currNoImmune++;
            }
        }

Then there are two loops that run until noIll and noHealthy and that's how agents are created so far. It works however not quite how I hoped it would. Numbers that are passed as arugments to createAgents() aren't being reflected on the map for all possible inputs. I realize that this task is beyond my capabilities since I've spend a good amount of time trying to figure it out, despite that I would still love to understand how it's done and how it can be achieved.

What I mean by fairly is as close to 50:50 as possible - whenever user inputs an uneven number of 3 immune, 1 animal and 2 civil agents there should be 2 immune civilians and 1 immune animal. Same logic shoud be extended to the missing parameters that is healthy and ill agents.