At the time that the Constitution was written, those that were enslaved, for purposes of how many seats that would be allocated to each individual State in the House of Representatives, were counted as: "three fifths of all other Persons," thereby providing for those States that enslaved fellow human beings, an entitlement of representation for an extra three fifths per person that was so enslaved. The 14th Amendment to our Constitution overturned the three fifths per person of those so enslaved, for slavery was eradicated by the 13th Amendment, and therefore the 14th Amendment counted the whole number of persons within each state for appropriate representation in the House of Representatives.
Since, the eradication of slavery, we have since progressed into a new era of strict immigration policies, of which, there are now millions upon millions of people residing in the United States of America that are not actually citizens of the United States, and further are considered to be illegal aliens and/or non-citizens within America, yet, these illegal aliens and non-citizens, are considered to be for purposes of representation within the respective States-- whole persons, that are counted exactly the same for such apportionment as those that are citizens. In short, every physical body within America, as recorded by the census every decade directly influences how many seats are allocated in the House of Representatives, thereby in its own way, rewarding those States that have more illegal aliens and non-citizens as residents of their States, with additional apportionment, at the expense of those States that do not.
Perhaps a better way to get a fairer allocation of representatives within each State, is not to count the physical bodies within the State, at all, but rather, count only those that specifically are enfranchised to vote, and only those that are actually registered to vote, as opposed to those that are of age, but have elected not to enfranchise themselves or have had such enfranchisement revoked, because of a felony conviction or similar. After all, the representatives within Congress should be a reflection of those that actually exercise their democratic right to vote, and the numbers of those representatives should be a true reflection of actual voters within that State.
If how many members of the house of representatives per State, was based not on the sheer numbers of people within a State, but the actual numbers of those so voting in that State, than each State would have a high incentive to get more people to register to vote and to actually vote within that State; in addition to probably deciding to re-enfranchise more of those that have previously been disenfranchised for a felony conviction or similar. This seems to be not only a fairer way to correctly apportion how many representatives that are allocated within each State, but a more honest reflection of what representation and voting should actually be about.
So too, with each member of the house of representatives up for election every two years, the census for such allocation numbers per State, should also be done every two years, and if it was based on who is eligible to vote, per the voter rolls, such would not be an overburden upon the States in appropriately knowing and counting how many voters each State actually has.