The apologetic site, AnswersinGenesis says there are at least five reasonable solutions for this problem, saying "if one or more of these solutions is correct then the alleged contradiction is eliminated":
- it is possible that all of the livestock except goats were killed in the first plague on the livestock (fifth plague overall), and in the second instance it was goats that were affected by the plague of hail.
The English language does not have a single word that means 'sheep and goats', and (for example) the KJV translates the Hebrew word וּבַצֹּ֑אן simply as 'sheep', but many other translations are possibly more accurate in saying 'sheep and goats'. It is highly speculative and therefore unlikely that an all-powerful God would have failed to kill the goats as well as the sheep.
- Exodus 9:19–20 mentions that those who “feared the word of the Lord among the servants of Pharaoh” were told to get their livestock out of the fields. Some scholars mention that these Egyptians may have been warned about the previous plague of pestilence (although it was not recorded), so they still had all of their livestock left. In this scenario, God warned them to put all of their livestock in barns so they wouldn’t be killed by hail.
This scenario requires God to be capricious, allowing these Egyptians to save their livestock in the first case, only to destroy them in the following one. As AnswersinGenesis implies, everything is possible, but a capricious God should not be considered a reasonable possibility.
- In Exodus 9:6, where it says that all the livestock of Egypt died, this view suggests that the animals belonging to these foreign vassals were spared if they obeyed God and not Pharaoh.
Verse 20, which says "He that feared the word of the LORD *among the servants of Pharaoh* made his servants and his cattle flee into the houses:
" thereby saving them from the hail of the second destruction of livestock. This proposal reads a particular meaning into 'servants of Pharaoh' as foreign vassals who feared the word of the LORD, and assumes that their cattle survived not only the second destruction but also the first. So far, so good, but this falls over because this proposal seems to allow no cattle to die in the second destruction. The servants whose cattle survived the first destruction also saved their cattle in the second destruction.
- The Egyptians may have taken some of the livestock belonging to Israel. Another possibility is that they bought (or took) livestock from surrounding areas (Libya, Ethiopia, Canaan, etc). The first option would require very little time to complete while the second would probably require at least a few weeks. But since the Bible does not specify how much time passed, either is possible.
In the first of these scenarios, the first destruction punished, not the Egyptians, but the Israelites, since the Egyptians were in a position to take their cattle as recompense for the destruction wrought by the Israelite God. I therefore reject this option because requires God to be unaware of the consequence of his action. In any case, Moses says in 10:26 "Our cattle also shall go with us; there shall not an hoof be left behind."
The second is only a little more likely because the replacement from neighbouring nations of perhaps a million cattle would be impossible in less than a period of years.
- The fifth, and perhaps simplest solution, would be to acknowledge the fact that “all” does not always mean exclusively “all.” We must use the context to determine its meaning. In the case of Exodus 9:6, it might be best translated that “all manner of livestock of the Egyptians died.”
This is a more plausible explanation than the previous four, but places the Bible in the position that it is not always literally accurate. If we "must use the context to determine its meaning" we can look at any biblical passage in the same way, an outcome that must concern a conservative group such as AnswersinGenesis.
In the Conclusion, AnswersinGenesis concedes the possibility that none of these proposals is true, and that there may be another solution it has not even addressed. My assessment, as indicated in the above comments, is that we must indeed look for another solution not even addressed here.
Laura Feldt (The Fantastic in Religious Narrative from Exodus to Elisha)
says Exodus contains several paradoxes that challenge the mimetic-illusionist assumptions of the reader. She says it is strange that the Egyptian cattle die in Exodus 9:6 and are alive again in verse 9:19, to be killed in another plague in 9:25. She says that in verse 10:25 Moses demanded that the Egyptians provide sacrifices and burnt offerings for the Israelites, even though the Egyptians no longer had any animals to offer.
Alan Silver (Jews, Myth and History, page 233) says that when the firstborn of all the Egyptian cattle are once again killed in Exodus 11:5, it is "a clear case of overkill!"
An alternative explanation
AnswersinGenesis provides a range of possible answers, none of which is very convincing. Feldt and Silver point to further instances in which the Egyptians still have cattle, in spite of the best efforts of God, as reported in the Book of Exodus, making the AnswersinGenesis explanations even more implausible.
Carol A. Redmount says, in 'Bitter Lives', published in The Oxford History of the Biblical World, page 63:
The biblical Exodus account was never intended to function or to be understood as history in the present-day sense of the word. For most occasions, and especially for documents that expressed deeper truths and fundamental values, facts as such were not always valued, consistency was not always a virtue, and specific historical particulars were often irrelevant and therefore variable.
According to Redmount and most modern scholars, the Book of Exodus was written long after the supposed events of the Exodus, with Redmount saying, recent research indicates that even more of the extant Exodus account than previously thought comes from periods during or after the Israelite monarchy or even the Exile.
The Jews of the exilic period needed a to believe in a past in which even the most powerful of their enemies could be defeated, and the Priestly Source provided this in the finalised account of the ten plagues. The Jewish audience would have exulted in the repeated stories of the Egyptians suffering as they themselves were now suffering. In these circumstances, there was no need for the various passages to be free of contradiction.